The document discusses the mechanical characteristics and processing of 6xxx series aluminium alloys, primarily containing silicon and magnesium, which are known for their heat treatability, formability, and corrosion resistance. It details methodologies including heat treatment, solution heat treatment, and microalloying with tin to enhance properties. The study finds that while microalloying with tin affects the microstructure, solution heat treatment may lead to grain growth and reduced alloy hardness.

2. TABLE OF CONTENTS
• INTRODUCTION
• OBJECTIVE OF THE STUDY
• 6XXX ALUMINIUM ALLOYS
• METHODOLOGY – HEAT TREATMENT, SOLUTION HEAT TREATMENT, AGEING (NATURAL &
ARTIFICIAL)
• MICROALLOYING WITH DIFFERENT PERCENTAGE OF SN
• CONTRIBUTION & WORK
• RESULT & DISCUSSION

3. INTRODUCTION
• 6XXX SERIES ALUMINIUM ALLOYS MAINLY CONTAINS SILICON (SI) AND
MAGNESIUM (MG) AT LARGER PROPORTIONS.
• IT IS HEAT TREATABLE, OFFERS GOOD FORMABILITY, WELDABILITY,
MACHINABILITY AND CORROSION RESISTANCE.
• WIDELY USED 6XXX ALUMINIUM ALLOYS ARE : 6005, 6061,6063,6082 & 6061.
• ONGOING RESEARCH TO ENHANCE MICROSTRUCTURE AND MECHANICAL
PROPERTIES OF THESE ALLOYS.

4. OBJECTIVE OF THE SURVEY
• TO STUDY IN BRIEF THE VARIOUS MECHANICAL CHARACTERISTICS OF THE
ALUMINIUN 6XXX SERIES ALLOYS ,WHEN SUBJECTED TO VARIOUS PROCESS
– HEAT TREATMENT, SOLUTION HEAT TREATMENT, AGEING- NATURALAND
ARTIFICIALAND MICROALLOYING WITH DIFFERENT COMPOSITIONS OF SN.

5. 6XXX SERIES ALLUMINIUM ALLOYS
• ALLOYS IN THE 6XXX SERIES CONTAIN SILICON AND MAGNESIUM APPROXIMATELY
IN THE PROPORTIONS REQUIRED FOR FORMATION OF MAGNESIUM SILICATE
(MG2SI), THUS MAKING THEM HEAT TREATABLE. 6XXX SERIES ALLOYS HAVE GOOD
FORMABILITY, WELDABILITY, MACHINABILITY, AND CORROSION RESISTANCE. 6061
ALLOY IS ONE OF THE MOST COMMONLY USED GENERAL PURPOSE ALUMINIUM
ALLOYS. SOME OTHER ALLOYS OF THIS SERIES ARE 6005, 6061, 6063, AND 6082. THE
ALLOY 6005 IS USED IN STRUCTURAL APPLICATIONS, 6060 HAS BETTER
EXTRUDABILITY, 6061 IS MOST VERSATILE OF HEAT TREATABLE GROUP HAVING
GOOD CORROSION RESISTANCE WHICH IS USED IN TRANSPORTATION AND
STRUCTURAL APPLICATIONS AND 6063 IS MOST POPULAR EXTRUSION ALLOY.

6. METHODOLOGY
THE VARIOUS METHODS USED FOR DIFFERENT TYPES OF 6XXX ALUMINIUN SERIES
ALLOYS ARE:
• HEAT TREATMENT
• SOLUTION HEAT TREATMENT
• AGEING (NATURAL AND ARTIFICIAL)

7. HEAT TREATMENT
THE 6000 SERIES ALLOYS ARE TYPICAL HEAT-TREATABLE ALUMINIUM ALLOYS WHICH GAIN
THEIR STRENGTH FROM THERMAL PROCESSING RATHER THAN MECHANICAL
DEFORMATION. THE KEY ELEMENTS OF THESE ALLOYS ARE MAGNESIUM (MG) AND SILICON
(SI) WHICH COMBINE TO FORM THE MG2SI PRECIPITATES.
FIG1: MICROSTRUCTURE OF THE PEAK AGING, INCLUDING (A) ALMGSI01 ALLOY WITH 0.02 WT% ZN; (B) ALMGSI02
ALLOY WITH 0.73 WT% ZN; (C) ALMGSI03 ALLOY WITH 3.72 WT% ZN; (D) THE ENLARGED VIEWS OF SELECTED REGION IN
(C).

8. SOLUTION HEAT TREATMENT:
HEAT TREATMENTS WITH PROPER PARAMETERS ARE CRITICAL TO FURTHER
IMPROVE THE PROPERTIES AND THE SOLUTION HEAT TREATMENT IS THE FIRST
STEP OF STRENGTHENING . THE SOLUTION TEMPERATURE HAS A SIGNIFICANT
IMPACT ON THE DEGREE OF SOLID SOLUTION.
FIG 2: MICROSTRUCTURE IMAGE OF ALMGSI02 ALLOY WITH 0.73 WT% ZN AT DIFFERENT SOLUTION
TEMPERATURE: (A) AS-CAST STRUCTURE; (B) 570°C; (C) 575°C; (D) 580°C.

9. AGEING – NATURALAND ARTIFICIALAGEING
• THE MICROSTRUCTURE CHANGES OF THE ALUMINIUM ALLOYS FOLLOWING AGING FOR
120 H WERE INVESTIGATED BY METALLOGRAPHIC OBSERVATIONS. AL 6005 AND 6082
SAMPLES WERE PREHEATED IN INDUCTION FURNACE AT TEMPERATURE 570°C AND HOLD
FOR 4 TO 6 H AND THEN COOLED USING DIFFERENT COOLING RATES (QUENCHING IN
WATER, OIL AND AIR COOLING OR SLOW FURNACE COOLING). WATER COOLED SAMPLES
WERE SUBJECTED TO T4 (SOLUTION HEAT TREATMENT AND NATURAL AGING).
• ARTIFICIAL AGEING IS DONE AT TEMPERATURE 185 C-185 C FOR 8HR FOLLOWED BY WATER
ᵒ ᵒ
QUENCHING.

10. FIG :(A) MICRO-VICKERS HARDNESS OF THE ALLOYS AT AS-CAST AND PEAK-AGED
CONDITIONS; (B) AGEING BEHAVIOR OF THE ALLOYS AT 190°C.

11. MICROALLOYING
• 6XXX SERIES ALLOYS ARE DIFFICULT TO CAST DUE TO THEIR LOW FLUIDITY. RESEARCHERS HAVE
EXPLORED VARIOUS CASTING TECHNIQUES FOR THE SOUND SHAPE CASTING OF THESE ALLOYS.
• ONE OF THE PRIME CONCERNS FOR THE INDUSTRIES IS TO ENABLE THE FORMING OPERATIONS AT
LOW STRENGTH. HENCE, THE AL–MG–SI ALLOYS ARE TRANSPORTED IN SEMI-FINISHED PRODUCT
FORM MOSTLY AFTER QUENCHING TO ENABLE FORMING OPERATIONS AT LOW STRENGTH PRIOR
TO THE FINAL HEAT TREATMENT TO GAIN HIGH STRENGTH.
• THE PROBLEM ARISES DURING THE TRANSPORTATION PERIOD, DURING WHICH THE FORMABILITY
OF THE ALLOY DECREASES DUE TO AN INCREASE IN HARDNESS AS A RESULT OF NATURALAGING.

12. CONCLUSION
• MICRO-ALLOYING SN HAS NO SIGNIFICANT EFFECT ON THE GRAIN SIZE OF THE
AL–MG–SI ALLOY
• SOLUTION HEAT TREATMENT RESULTS IN THE GRAIN GROWTH, DISSOLUTION
AND COARSENING OF THE INTERMETALLIC PARTICLES AND THUS
SIGNIFICANTLY DECREASES THE HARDNESS OF THE ALLOYS.
• MICRO-ALLOYING 0.04 WT% SN FAVOURS THE FORMATION OF A LAMELLA-LIKE
EUTECTIC AL2MG2SI, WHEREAS MICRO-ALLOYING 0.08 WT% SN FAVOURS THE
FORMATION OF PLATE/ROD-LIKE MG2SI.