EFFECT OF POST WELD HEAT TREATMENT ON FRACTURE TOUGHNESS PROPERTIES OF FRICTION STIR WELDED AA7075-T651 ALUMINIUM ALLOY JOINTS
Keywords:
AA 7075 aluminium alloy, Friction stir welding, Fracture toughness, post weld heat treatmentAbstract
This paper reports on investigation of the effect of post weld heat treatment on fracture toughness properties of friction stir welded AA7075-T651 aluminium alloy joints. The aim of the present work is to evaluate the effect of post weld heat treatment on fracture toughness properties of 12 mm thick AA 7075 -T651 aluminium alloy plates joined by friction stir welding (FSW) process. Compact tension (CT) specimens were prepared to evaluate the plane strain fracture toughness of the welded joints. The fracture toughness properties were evaluated under uniaxial tensile loading condition (stress ratio = 0.1, Frequency =10Hz) at room temperature using servo-hydraulic controlled machine. The resultant fracture toughness properties were correlated with the tensile, hardness and microstructural characteristics of welded joints. The mode of failure was analyzed through scanning electron microscopy. From this investigation, it is found that the fracture toughness values of friction stir welded AA7075 aluminium alloys are lower than that of the fracture toughness values of friction stir welded post weld heat treatment (solution treated followed by aging (STA)) joints.
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