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Recrystallization microstructures and textures in aa 5052 continuous
 

Recrystallization microstructures and textures in aa 5052 continuous

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    Recrystallization microstructures and textures in aa 5052 continuous Recrystallization microstructures and textures in aa 5052 continuous Document Transcript

    • Materials Science and Engineering A 385 (2004) 342–351 Recrystallization microstructures and textures in AA 5052 continuous cast and direct chill cast aluminum alloy Jiantao Liua,b,c,∗ , James G. Morrisb a Material Science and Engineering Laboratory, National Institute of Standards and Technology, Gaithersburg MD 20899-8553, USA b Department of Chemical and Materials Engineering, University of Kentucky, Lexington KY 40506-0046, USA c Physics Department, Catholic University of America, Washington DC 20064, USA Received 4 December 2003; received in revised form 21 June 2004Abstract Commercially produced hot bands of AA 5052 continuous cast (CC) and direct chill (DC) cast aluminum alloys were cold rolled to (thickness)reductions of 70%, 80%, and 90% followed by annealing at different conditions. The recrystallization kinetics are found equivalent for both theCC and DC materials. Recrystallization microstructures are different between the CC and DC materials. Evolution of recrystallization texturein the CC and DC materials were investigated by using three-dimensional orientation distribution functions (ODFs) that were determined byX-ray diffraction. The recrystallization texture was correlated with cold rolling reduction (prior to annealing), annealing temperature, andannealing time. Results showed that the R {124} 211 and cube {001} 100 are dominant recrystallization texture components in both CC andDC materials. During annealing, the intensity and volume fraction of the cube component strongly depend on the prior cold rolling history. Incontrast, the intensity and volume fraction of the R component remains almost constant regardless of the different cold rolling reductions priorto annealing. After complete recrystallization, the intensity and volume fraction of both R and cube components appear to be independent ofthe annealing temperature and annealing time.© 2004 Elsevier B.V. All rights reserved.Keywords: Aluminum alloy; Recrystallization; Texture1. Introduction nization, hot rolling, annealing, cold rolling and an optional final annealing. An alternative way for production of alu- Growth in the automotive industry and the demand for minum alloy sheets, starts from continuous cast (CC) slab,weight reduction of vehicles have opened the door for auto- which involves only hot rolling, cold rolling and an optionalmotive application of Al-Mg (AA 5XXX) alloys. The plastic final annealing. Note that CC slab with thickness less thananisotropy, determined by texture, is of critical importance 25.4 mm, formed from liquid alloys by caster, was directlyin affecting deep drawing properties of sheet products. Con- fed into hot rolling mills without any homogenization and/orsequently, the challenge to produce Al-Mg sheets with con- prior reduction. Therefore, CC materials compare favorablytrolled anisotropic mechanical properties has drawn much with DC materials in lower energy consumption and higherattention in recent years. productivity. DC material undergoes extensive thermome- The conventional production of aluminum alloy sheets, chanical processing that results in significant breakdown ofstarting from direct chill (DC) cast ingot, includes homoge- the cast structure. On the other hand, most of the cast struc- tures are retained in CC material and are deformed producing ∗ Corresponding author: Alcoa Technical Center, 100 Technical Drive, a banded intermetallic structure in which the spatial distribu-Alcoa Center, PA 15069-0001, USA. tion of particles is not uniform. It has been found that this E-mail address: jiantao.liu@alcoa.com (J. Liu). banded intermetallic structure may significantly affect the0921-5093/$ – see front matter © 2004 Elsevier B.V. All rights reserved.doi:10.1016/j.msea.2004.06.070
    • J. Liu, J.G. Morris / Materials Science and Engineering A 385 (2004) 342–351 343subsequent recrystallization behavior and texture of Al-Mn 950 ml water) the samples were electropolished using a so-(AA 3XXX) alloys [1–3]. lution of 15 ml HNO3 and 50 ml HClO4 acids in 950 ml Previous investigations of Al-Mg alloys have focused on methanol to remove the deformation layer. The microstruc-texture evolution of the DC materials during hot rolling [4–6], tures were examined using light microscopy under polarizedannealing [7–9], and cold rolling [7,9–11]. However, infor- light. The grain size was determined by a linear interceptmation about the recrystallization texture evolution of CC method.materials during annealing is still lacking to date. It is there-fore imperative that comparison in recrystallization and tex- 2.3. Crystallographic texture measurementture behavior between CC and DC Al-Mg alloys be made sothat the difference can be highlighted. Samples for crystallographic texture measurements were This work has been conducted in an effort to study sectioned in the rolling plane (normal to the RD and to thethe recrystallization behavior of commercial AA 5052 (Al- transverse direction (TD)) at the half-thickness position. The2.4 wt.% Mg) CC and DC materials during annealing. Specif- surface for measurement was carefully polished to minimizeically, the effects of cold rolling reduction, annealing temper- surface stress. Three incomplete pole figures {111}, {200}ature (TA ) and annealing time (tA ) on the microstructure and and {220} were measured (αmax = 75◦ ) using Cu K␣ radi-texture evolutions were investigated. Therefore, it was the ation by means of the Schulz reflection method [12]. Allpurpose of this work to provide information that enables op- incomplete pole figure data were corrected for defocusingtimization of thermomechanical processing parameters for error and background intensity. Three-dimensional orienta-AA 5052 CC material. Another focus of this work was to tion distribution functions (ODFs) f(g) were calculated bycompare the microstructure and texture of both CC and DC using the arbitrarily defined cell (ADC) method [13,14]. Thematerials during recrystallization. orientations g were visualized in Euler space defined by three Euler angles ϕ1 , Φ, ϕ2 in the range of 0◦ ≤ ϕ1 , Φ, ϕ2 ≤ 90◦ . Each texture component is fitted using a Gauss-type scatter-2. Experimental ing function for quantitative analysis [15,16]. Therefore, the volume fraction Mi of each texture component i was calcu- i lated by determining the central orientations g0 , the maxi-2.1. Materials and procedures mum intensity (height) si (g0 i ), the scattering width ψ , and i Commercial alloy AA 5052 CC and DC hot bands with the symmetrical multiplicity Zicompositions shown in Table 1 were used for the exper- Zi ψ2iments. The thickness of the CC and DC hot bands was Mi = si (g0 )ψi 1 − exp − i i (1)4.06 and 3.67 mm, respectively. In order to generate a com- 2π1/2 4pletely recrystallized microstructure before cold rolling, theas-received hot bands were annealed at 823 K for 7200 s fol-lowed by water quenching. The quenched hot bands were ho- 3. Results and discussionmogeneously cold rolled at room temperature to 70%, 80%,and 90% reductions in thickness. In the following annealing 3.1. Microstructure and texture of cold rolled hot bandsprocess, samples were then cut from cold rolled hot bandsand annealed at 573 K, 673 K, and 773 K for 20 s, 50 s, 100 s, Fig. 1 shows the microstructures of hot bands after 90%250 s, 550 s, 750 s, 1000 s, 5500 s, 104 s, and 105 s followed cold rolling. The grains are severely elongated along theby a water quenching. RD for both CC (Fig. 1(a)) and DC (Fig. 1(b)) materials, which characterizes typical deformation grain structures of2.2. Microstructure examination aluminum alloys. There is not a significant difference in the grain structures between the CC and DC materials. However, Samples for microstructure examination were cut from CC material (Fig. 1(c)) contains a banded constituent particlethe cold rolled hot bands on planes normal to the nor- structure (mostly Al-Fe-Mn crystallized phase that is identi-mal direction (ND) and to the rolling direction (RD), cold fied by energy dispersive spectrometer (EDS)) along the RD,mounted and ground to about 600 grit using SiC paper. The while the DC material (Fig. 1(d)) is featured by a uniformlysurface of the samples was polished using 1 ␮m alumina. distributed particle structure.Prior to anodizing using Barker’s reagent (50 ml HBF4 in Fig. 2 illustrates the ODFs (Fig. 2(a)) and the orientation intensity of orientations along the ␤ fiber (Fig. 2(b)) of CC hotTable 1 band after 70%, 80%, and 90% cold rolling. For the ODFs,Compositions of experimental materials, as mass fractions multiplied by 100 only three sections of ϕ2 = 45◦ , ϕ2 = 60◦ , and ϕ2 = 90◦ , wereAlloy Si Fe Cu Mn Mg Zn Cr Al given in order to highlight the Copper, S/R, and cube/Brass orientations, respectively. After 70% cold rolling reduction,AA 5052 CC 0.13 0.35 – 0.03 2.40 0.02 0.18 BalanceAA 5052 DC 0.10 0.39 0.02 0.03 2.39 – – Balance the texture is characterized by a retained cube orientation {001} 100 accompanied by a well developed ␤ fiber spread-
    • 344 J. Liu, J.G. Morris / Materials Science and Engineering A 385 (2004) 342–351 Fig. 2. (a) ODFs (at sections of ϕ2 = 45◦ , 60◦ and 90◦ ) and (b) the intensity of orientations along the ␤ fiber (skeleton line) of cold rolled AA 5052 CC hot band with cold rolling (CR) reductions of 70%, 80% and 90%.Fig. 1. Grain structure of AA 5052 alloy for (a) CC and (b) DC materialsand particle structure of AA 5052 alloy for (c) CC and (d) DC materials after cube orientation of the DC material remains at 6.2, which90% cold rolling. is much higher than the CC material at the same reduction. Additionally noted, the intensity of orientations along the ␤ing from the Brass orientation {011} 211 through the S ori- fiber is below 3.5. The cube orientation transforms to the Gossentation {123} 634 to the Copper orientation {112} 111 . orientation {011} 100 along the RD and further to the BrassThe cube orientation rotates about ND and yields a weak orientation through the ␣ fiber with increase in cold rollingcubeND orientation. During further cold rolling, grains rotate reduction in the same way as the CC material. It can be seenfrom the cube orientation to the Goss orientation {011} 100 that the cube orientation is retained even after cold rollingand then toward the Brass orientation along the cubeRD and with a 90% reduction. The intensity of the orientations along␣ fibers. As a result, the intensity of the Brass orientation in- the ␤ fiber (Fig. 3(b)) is lower than that of the CC material.creases while the intensity of the cube orientation decreases The highest intensity is also found at (ϕ1 , , ϕ2 ) = (65◦ , 30◦ ,with increasing cold rolling reduction (Fig. 2(a)). After 90% 60◦ ), which is the same as that of CC material. As can be seencold rolling, the cube orientation disappears. For all three cold in Figs. 2 and 3, the orientation (ϕ1 , , ϕ2 ) = (65◦ , 30◦ , 60◦ )rolling reductions, the highest intensity is found at (ϕ1 , , ϕ2 ) becomes the strongest orientation along the ␤ fiber, which= (65◦ , 30◦ , 60◦ ) that is located between the Copper and S indicates inhomogeneous development of the ␤ fiber duringorientations (Fig. 2(b)). cold rolling in both CC and DC materials. In general, the The textures of cold rolled DC hot band are shown in texture evolution of DC material appears similar to that ofFig. 3(a). At 70% cold rolling reduction, the intensity of the CC material except that the evolution is delayed in the DC
    • J. Liu, J.G. Morris / Materials Science and Engineering A 385 (2004) 342–351 345 Fig. 4. Microhardness vs. annealing time of cold rolled (cold rolling (CR) reductions of 70%, 80%, and 90%) AA 5052 (a) CC and (b) DC materialsFig. 3. (a) ODFs (at sections of ϕ2 = 45◦ , 60◦ and 90◦ ) and (b) the intensity at annealing temperatures of 573 K, 673 K, and 773 K.of orientations along the ␤ fiber (skeleton line) of cold rolled AA 5052 DChot band with cold rolling (CR) reductions of 70%, 80% and 90%.material, which can be attributed to the strong initial cubeorientation in the DC material [11]. ing annealing at different temperatures (Fig. 4(b)) are quite similar to those of CC materials shown in Fig. 4(a). The time required for complete recrystallization of AA 5052 CC and3.2. Recrystallization kinetics DC samples under different cold rolling reductions are given in Figs. 5(a) and 5(b), respectively. Dash lines indicate the The progress of recrystallization during annealing was ex- starting time for recrystallization, while the solid lines indi-amined by using microhardness supported by examinations cate the time required for complete recrystallization. Whileof microstructure and texture. Fig. 4 presents the change of the time required for complete recrystallization appears to bemicrohardness versus annealing time tA of CC and DC ma- independent of cold rolling reduction for both materials an-terials during annealing at temperatures of 573 K, 673 K, and nealed at either 673 K and 773 K, the time required for com-773 K. It can be seen that higher annealing temperature leads plete recrystallization decreases with increasing cold rollingto earlier starting time for recrystallization. The starting time reduction when the annealing temperature is 573 K. Similarfor recrystallization shifts from about 1000 s at 573 K anneal- results are also reported for a Al-1.8 wt.% Cu alloy [17]. Ining to about 60 s at 773 K annealing (Fig. 4(a)). The curves of general, there is no remarkable difference of recrystallizationmicrohardness versus annealing time tA of DC material dur- kinetics between CC and DC materials.
    • 346 J. Liu, J.G. Morris / Materials Science and Engineering A 385 (2004) 342–351Fig. 5. Effect of cold rolling reduction on recrystallization (RX) progress ofAA 5052 (a) CC and (b) DC materials at annealing temperatures of 573 K,673 K, and 773 K.3.3. Recrystallization microstructure Recrystallization grain structure of the CC material af-ter 70%, 80%, and 90% cold rolling followed by annealingat 673 K for 1000 s are shown in Figs. 6(a) through 6(c),respectively. They clearly show that recrystallization grainsize decreases with increasing cold rolling reduction priorto annealing, which can be explained by strain induced nu-cleation. It is worth pointing out that there exists a band of Fig. 6. Grain structure of AA 5052 CC material after (a) 70%, (b) 80% andRD elongated grain structures in the CC material at about the (c) 90% cold rolling followed by annealing at 673 K for 1000 s.half-thickness layer as indicated by arrows. The average ratioof the dimension in the RD to the dimension in the ND of The recrystallized grain size was averaged between thethe grains in the banded structures is about 4:1. This banded dimensions in the ND and in the RD. The average recrystal-grain structure was also observed in all other completely re- lized grain size of the microstructures shown in Figs. 6 and 7crystallized samples of the CC material in this work. Char- is plotted versus cold rolling reduction in Fig. 8, where solidacterization of this banded grain structure, beyond the scope symbols stand for the average grain size of grains at the centerof this study, will be presented elsewhere. Fig. 7 shows the layer (from quarter- to half-thickness), while the open sym-recrystallized grain structures of cold rolled DC hot bands. bols represent average grain size of grains at the surface layerThe banded grain structure observed in CC material is absent (from surface to quarter-thickness). Generally, the average re-in the DC material. Instead, an equiaxied grain structure is crystallized grain size on the surface layer is smaller than thatformed after annealing at 673 K for 1000 s of 70% (Fig. 7(a)), at the center layer for both the CC and DC materials. For the80% (Fig. 7(b)), and 90% (Fig. 7(c)) cold rolled specimens, CC material with 70% reduction, the average recrystallizedrespectively. grain size is about 25.5 ± 1.3 ␮m at the center layer, while
    • J. Liu, J.G. Morris / Materials Science and Engineering A 385 (2004) 342–351 347 Fig. 8. Dependence of recrystallized grain size on cold rolling reduction of AA 5052 for the CC and DC materials after annealing at 673 K for 1000 s. average recrystallized grain size between surface and center layers are 7 ␮m and 4 ␮m for the CC and DC materials with 90% cold rolling reduction prior to annealing, respectively. In general, the grain size distribution between surface and cen- ter layers in the CC material is more inhomogenuous than that in the DC material. 3.4. Texture evolution during recrystallization 3.4.1. Effect of cold rolling reduction (prior to annealing) Fig. 9 shows the recrystallization texture of the CC and DC materials after cold rolling followed by annealing. After annealing of the CC material, the intensity of the cube orien- tation increases rapidly from 3.1 in specimen with 70% cold rolling reduction to 7.7 in specimen with 90% cold rolling reduction (Fig. 9(a)). For the DC material, the intensity of the cube orientation reaches 11.9 in specimen with 90% cold rolling reduction, which increases from 4.6 in specimen with 70% cold rolling reduction for the DC material (Fig. 9(b)). The intensity of the R orientation {124} 211 slightly in- creases with increasing cold rolling reduction for both the CC and DC materials after annealing. The copper orientation {112} 111 , even though weak, is retained in all samples. These results indicate that the cube is a major recrystalliza-Fig. 7. Grain structure of AA 5052 DC material after (a) 70%, (b) 80% and tion texture component for AA 5052 alloy. Increasing the(c) 90% cold rolling followed by annealing at 673 K for 1000 s. cold rolling reduction strongly favors the formation of the re- crystallization texture, especially, the cube orientation duringit is just 10.9 ± 0.5 ␮m on the surface layer. The average re- annealing. Moreover, the retained cube component in the DCcrystallized grain sizes at center and on the surface layers of material with 90% cold rolling reduction (Fig. 3(a)) appearsDC material with 70% reduction is 21.5 ± 1.1 ␮m and 15.0 to substantially enhance the nucleation of the cube orientation± 0.8 ␮m, respectively. Therefore, the difference of average during annealing (Fig. 9(b)).grain size between surface and center layers for the CC ma- Beck and Hu [18] proposed two mechanisms explainingterial is larger than that for the DC material. This difference, the origin of the R orientation: (1) The R orientation is re-however, is significantly reduced with increase in cold rolling tained from the previous rolling texture by extended recoveryreduction prior to annealing. As a result, the differences of reactions such as continuous recrystallization (in situ recrys-
    • 348 J. Liu, J.G. Morris / Materials Science and Engineering A 385 (2004) 342–351 ison with cold rolled material (Fig. 2(a)). In contrast, ODFs significantly changed upon annealing of 90% cold rolled CC material (Fig. 9(a)) in which the cube texture is well devel- oped as compared to the ODFs of 90% cold rolled CC ma- terial (Fig. 2(a)). ODFs results (Fig. 9) also indicate that a higher the cold rolling reduction yields a higher intensity of the R orientation after annealing. The above results sug- gest that the retained mechanism overwhelms the nucleation mechanism at 70% cold rolling reduction. However, the nu- cleation mechanism becomes dominant with increasing cold rolling reduction. Similar transition from nucleation mech- anism to retention mechanism is also effective in the DC material (Fig. 3(a) and Fig. 9(b)). The effect of cold rolling reduction on the volume frac- tion of various texture components in CC and DC materials after cold rolling followed by annealing at 673 K for 1000 s are given in Figs. 10(a) and 10(b), respectively. For the CC material (Fig. 10(a)), the volume fraction of the cube compo- nent increases from about 5% at 70% cold rolling reduction to about 8% at 90% cold rolling. The volume fraction of the R component, though lower in intensity, is higher than that ofFig. 9. ODFs (at sections of ϕ2 = 45◦ , 60◦ and 90◦ ) of cold rolled AA 5052(a) CC and (b) DC hot bands with cold rolling (CR) reductions of 70%, 80%and 90% followed by annealing (AN) at 400 ◦ C for 1000 s.tallization) [17,19–22]; (2) R orientated grains form throughdiscontinuous recrystallization (genuine recrystallization) bynucleation at the grain boundaries within S oriented grains[21–25]. For the second mechanism, high strains favor theformation of R orientated grains, since they preferably nu-cleate at the grain boundaries [21]. In most cases, both mech-anisms take place by a competition process during annealing.As shown in Figs. 2 and 3, the highest intensity along the ␤fiber for cold rolled materials is located close to the S orien-tation, where the R orientation (ϕ1 , , ϕ2 ) = (65◦ , 30◦ , 60◦ )occupies after annealing. The cold rolled CC materials werecompletely recrystallized after annealing at 673 K for 1000 s(Fig. 6). After annealing of the 70% cold rolled material, Fig. 10. Effect of cold rolling reduction on the volume fraction of textureno remarkable transformation of the ODFs (Fig. 9(a)) was components in AA 5052 (a) CC and (b) DC materials after cold rolling (CR)found except for weakened deformation textures in compar- followed by annealing at 673 K for 1000 s.
    • J. Liu, J.G. Morris / Materials Science and Engineering A 385 (2004) 342–351 349the cube component. Therefore the R orientation {124} 211is identified as another major recrystallization texture com-ponent as well as the cube orientation. The volume fractionof the Brass component drops by about 4% with increasingcold rolling reduction, while the volume fraction of the Cop-per component remains at a very low level. It can also beseen that the volume fraction for random orientations keepsat about 70%. The volume fraction changes of the DC ma-terial (Fig. 10(b)) appear similar to that of the CC material(Fig. 10(a)). Again, the volume fraction of the R componentis higher than that of the cube component. It can also be seenthat the volume of the cube component increases by about 6%,while the volume fraction of the Copper component drops byabout 6% when cold rolling reduction increased from 70%to 90%. The volume fractions of the Goss and Brass compo-nents are low in the DC material.3.4.2. Effect of annealing temperature Fig. 11(a) shows the effect of annealing temperature onthe texture evolution of the CC material. While the typicaldeformation texture components Copper, Brass and S areretained at 573 K annealing without recrystallization, re-crystallization texture components cube and R are dominantin samples annealed at 673 K and 773 K. Microstructure(Fig. 6) and microhardness (Fig. 4(a)) results also verifythat a complete recrystallization state is achieved for all coldrolled hot bands annealed at 673 K for 1000 s. The ODFsresults (Fig. 11(a)) indicate that increasing the annealingtemperature does not increase the intensity of either the cubeorientation or the R orientation if a complete recrystalliza-tion has already been achieved. Similar effect of annealingtemperature on the texture evolution was also found in theDC material (Fig. 11(b)). For both the CC and DC materials,the intensity of the R orientation slightly decreases withincreasing annealing temperature. The intensity of the cubeorientation slightly increasing in the DC material withincrease in annealing temperature, however, decreases in Fig. 11. ODFs (at sections of ϕ2 = 45◦ , 60◦ and 90◦ ) of cold rolled AAthe CC material with increasing annealing temperature. It 5052 (a) CC and (b) DC hot bands with cold rolling (CR) reduction of 80%has been reported that increasing the annealing temperature followed by annealing (AN) at 573, 673 and 773 K for 1000 s.reduces the strength of the R orientation in favor of the cubeorientation [21,22], which, therefore, is merely supported by dition (Fig. 12(a)), while the volume fraction of the copperthe results from DC material in this study. component decreases by about 6% for the DC material at Fig. 12 illustrates the effect of annealing temperature on the same condition (Fig. 12(b)). About 4% of the Copperthe volume fraction of different texture components. There component remains for both materials. It is interesting tois not a significant increase in the volume fraction of both note that the Brass component disappears in the DC material,the cube and R components in either the CC (Fig. 12(a)) or while about 5% of the Brass component is retained in theDC (Fig. 12(b)) materials when the annealing temperature CC material after 773 K annealing. In both the CC and DCincreases from 673 K to 773 K, which indicates that the materials, the volume fraction of the random orientationsvolume fraction of the cube and R components does not increases rapidly from the deformed state (573 K annealing)increase with increasing annealing temperature if a complete to the recrystallized state (673 K annealing). The volumerecrystallization state has already been achieved. In general, fraction of the random orientations, however, remians almostthe volume fraction of the deformation texture components constant for annealing temperatures higher than 673 K.in both materials decreases with increasing annealingtemperature. The volume fraction of the Copper component 3.4.3. Effect of annealing timedrops rapidly from about 20% at 573 K annealing to about Fig. 13 shows the intensity of the cube and R orientations4% at 773 K annealing for the CC material at the same con- versus annealing time of both the CC and DC materials during
    • 350 J. Liu, J.G. Morris / Materials Science and Engineering A 385 (2004) 342–351 annealing at 673 K. It has been shown that the starting time for recrystallization is about 250 s (Figs. 4 and 5). The intensity of the cube orientation increases with annealing time up to 1000 s and thereafter remains stable during further annealing. Note that a complete recrystallization is achieved at about 1000 s for both materials (Figs. 4–7). The R orientation, upon forming at about 1000 s, remains almost a constant intensity during the annealing. These results indicate that the intensity of the cube and R orientations is independent of annealing time if complete recrystallization is achieved. The effect of annealing time on the volume fraction of various texture components in CC (Fig. 14(a)) and DC (Fig. 14(b)) materials are quite similar. The volume frac- tion of all texture components significantly changes between 250 s and 1000 s, when recrystallization occurs. It can be seen that volume fraction of the cube, R and random orientations increases, while the volume fraction of the Brass, S, and Cop- per decreases. For both the CC and DC materials, the volume fraction of the cube and R orientations remains almost con- stant after a complete recrystallization state is achieved atFig. 12. Effect of annealing temperature on the volume fraction of texturecomponents in AA 5052 (a) CC and (b) DC materials after 80% cold rolling(CR) followed by annealing for 1000 s.Fig. 13. Effect of the annealing time on the intensity of the cube and R Fig. 14. Effect of the annealing time on the volume fraction of texture com-texture components AA 5052 alloy after 80% cold rolling (CR) followed by ponents in AA 5052 (a) CC and (b) DC materials after 80% cold rollingannealing at 673 K. (CR) followed by annealing at 673 K.
    • J. Liu, J.G. Morris / Materials Science and Engineering A 385 (2004) 342–351 3511000 s. Further annealing beyond 1000 s does not lead to a Department of Commerce, or the United States Government,remarkable change of the volume fraction of various texture nor does it imply that the identified equipment or software iscomponents. The volume fraction of the R orientation, which the best available.is about 13% after complete recrystallization for both mate-rials, is higher than that of the cube orientation although theintensity of the R orientation is lower than that of the cube Referencesorientation. About 4% of the Copper component is retainedin both materials. [1] M. Somerday, F.J. Humphreys, Mater. Sci. Forum 331–337 (2000) 703–714. [2] M. Somerday, F.J. Humphreys, Mater. Sci. Technol. 19 (2003) 20–29. [3] J. Liu, J.G. Morris, Metall. Mater. Trans. A (2003) 34A.4. Conclusions [4] H.B. McShane, C.P. Lee, T. Sheppard, Mater. Sci. Technol. 6 (1990) 428–440. The recrystallized grain size of AA 5052 alloy is strongly [5] P.A. Hollinshead, Mater. Sci. Technol. 8 (1992) 57–62.affected by cold rolling reduction prior to annealing. The re- [6] B. Ren, Z. Li, C. Li, S. Ding, J.G. Morris, in: J.J. Jonas, T.R. Bieler, K.J. Bowman (Eds.), Advances in Hot Deformation Texturescrystallized grain size can be significantly refined by increas- and Microstructures, TMS, Warrendale, PA, 1993, pp. 207–221.ing cold rolling reduction prior to annealing. A banded re- [7] K. Hasegawa, T. Fujita, K. Araki, S. Mitao, K. Osawa, M. Niikura,crystallized grain structure layer with elongated grains along K. Ohori, Mater. Sci. Eng. A A257 (1998) 204–214.the rolling direction is found in CC material. [8] S. Li, S. Kang, H. Ko, Metall. Mater. Trans. A 31A (2000) 99– The R {124} 211 and cube {001} 100 orientations are 107. [9] J. Liu, Ph.D. Thesis, University of Kentucky: Lexington, KY, 2003.dominant recrystallization texture components in AA 5052 [10] B. Ren, J.G. Morris, in: P.L. Morris (Ed.), Aluminum Alloys foralloy. The volume fraction of the cube orientation increases Packaging, TMS-AIME, Warrendale, PA, 1992, pp. 121–136.with increasing cold rolling reduction prior to annealing. The [11] J. Liu, J.G. Morris, Metall. Mater. Trans. A 34A (2003) 951–966.intensity of the cube orientation is higher in AA 5052 DC [12] L.G. Schulz, J. Appl. Phys. (1949) 20.material than in AA 5052 CC material. [13] K. Pawlik, Phys. Stat. Sol. (b) 134 (1986) 477–483. [14] K. Pawlik, J. Pospiech, K. L¨ cke, Textures Microstruct. 14–18 (1991) u During annealing, the most important recrystallization 25–30.texture evolution occurs before a complete recrystallization [15] J. Pospiech, K. L¨ cke, Acta Metall. 23 (1975) 997–1007. ustate is achieved. Once the complete recrystallization state is [16] K. L¨ cke, J. Pospiech, J. Jura, J. Hirsch, Z. Metall. 77 (1986) uachieved, the recrystallization texture can not be significantly 312–321.changed by either increasing the annealing temperature or in- [17] O. Engler, J. Hirsch, K. L¨ cke, Acta Metall. Mater. 43 (1995) u 121–138.creasing the annealing time. [18] P.A. Beck, H. Hu, Trans. AIME 194 (1952) 83–90. [19] K. Ito, R. Musick, K. L¨ cke, Acta Metall. 31 (1983) 2137–2149. u [20] J. Hirsch, K. L¨ cke, Acta Metall. 33 (1985) 1927–1938. uAcknowledgements [21] O. Engler, H.E. Vatne, E. Nes, Mater. Sci. Eng. A205 (1996) 187–198. [22] O. Engler, Metall. Mater. Trans. A 30A (1999) 1517–1527. Financial support from the United States Department of [23] R.D. Doherty, Metal Sci. 8 (1974) 132–142.Energy (under Contract No. DE-FC07-01ID14193) is grate- [24] A. Oscarsson, W.B. Hutchinson, H.-E. Ekstr¨ em, Mater. Sci. Tech- ofully acknowledged. Identification of equipment or software nol. 7 (1991) 554–564.does not imply recommendation or endorsement by NIST, the [25] O. Engler, Mater. Sci. Technol. 12 (1996) 859–872.