Effect of Post-Weld Heat Treatment on Microstructure and Mechanical Properties of AA7075 Welds

Subject Areas : welding

Alireza  Jalil ¹ (Faculty of mechanical engineeringShahid rajaee teacher training university)
Nasrollah  Bani Mostafa Arab ² (Department of Mechanical Engineering,Shahid Rajaee Teacher Training University, Iran)
Malek  Naderi ³ (Department of Mining and Metallurgical Engineering, Amirkabir University of Technology)
Yaghoub  Dadgar Asl ⁴ (دانشگاه فنی و حرفه ای)

Received: 2023-08-17 Accepted : 2023-11-30 Published : 2024-02-24

Keywords: AA7075, Mechanical Properties, Post-Weld Heat Treatment, TIG Welding ,

Abstract :

The attractive mechanical properties of 7075 alloy, such as its high strength-to-weight ratio and fracture toughness, have received special attention in the automotive and aerospace industries. However, welding as a fabrication process has a detrimental effect on this alloy’s properties which affects its mechanical performance. In this work, to compensate for the loss in mechanical properties caused by welding, proper heat treatment operations are adopted. To this end, 1.5 mm AA7075 sheets were first preheated and butt welded using the gas tungsten arc welding process. The welded sample was solution heat treated, quenched, and then artificially aged. Microhardness tests showed an increase of hardness in all zones of the aged specimen compared to those of the original welded blank before heat treatment. A maximum microhardness value of 180 HV was recorded in the heat-affected zone of the aged specimen. In addition, elongation at break, and strength (yield, tensile, and fracture) of the original welded blank increased by about 50% after the artificial aging operation.

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