Effect of different pre- and post-weld heat treatments on microstructures and mechanical properties of variable polarity TIG welded AA2219 joints. (2nd April 2016)

• Record Type: Journal Article
• Authors: Lin, Y. T.; Wang, D. P.; Wang, M. C.; Zhang, Y.; He, Y. Z.
• Is Part Of: Science and technology of welding & joining. Volume 21:Number 3(2016)
• Page Start: 234
• Page End: 241
• Publication Date: 2016-04-02
• Subjects: Microstructures -- Mechanical properties -- Heat treatment -- Intermediate state welding -- Variable polarity TIG -- 2219 aluminium alloy; Welding -- Periodicals; Joints (Engineering) -- Periodicals; Surfaces (Technology) -- Periodicals; 671.52
• DOI: 10.1179/1362171815Y.0000000087
• Languages: English
• ISSNs: 1743-2936

Abstract

Abstract : The microstructures and mechanical properties of 2219 aluminium alloy joints welded by variable polarity TIG welding in four kinds of different heat treatment conditions, namely, with/without pre-/post-weld heat treatment, were analysed and compared. The post-weld artificial aging treatment rendered fine dispersed precipitates (metastable θ′ phase) separate out of weld metal, which made the hardness of weld metal increase by ∼20%. Meanwhile, the fracture location of joints during tensile test changed from weld zone to heat affected zone (HAZ). The pre-weld solution treatment reduced the overaging degree of HAZ and a large number of θ′ phase reprecipitated in HAZ after post-weld artificial aging treatment. Intermediate state welding, with pre-weld solution treatment and post-weld artificial aging treatment together, could increase 20% of the hardness of weld zone, increase 11.5% of the hardness of HAZ and increase 20.3% of the tensile strength of joint.