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讨论了焊后热处理对Ti Al合金与40Cr热轧钢摩擦焊接头显微组织及力学性能的影响。焊态下,钢侧界面层附近发生马氏体转变,界面层中碳原子富集生成Ti C,降低了接头的力学性能;Ti Al合金侧形成了羽毛状及魏氏体组织。经580°C和630°C保温2 h焊后热处理,界面层附近形成回火索氏体组织,碳弥散分布,接头的抗拉强度由焊态时的86 MPa分别提高至395 MPa和330 MPa。焊态下,接头沿界面层断裂;热处理后,接头呈准解理断裂,断裂位置位于Ti Al合金侧,距界面层约1 mm。
The effects of postweld heat treatment on the microstructure and mechanical properties of the friction stir welded TiAl alloy and 40Cr hot rolled steel were discussed. In the as-welded state, the martensite transformation occurred near the interface layer on the steel side, and the carbon atoms in the interface layer were enriched to form TiC, which reduced the mechanical properties of the joint. Fe-like and Westenitic structures were formed on the TiAl alloy side. After heat treatment at 580 ° C and 630 ° C for 2 h, the tempered sorbite and carbon are distributed in the vicinity of the interface layer, and the tensile strength of the joint increases from 86 MPa to 395 MPa and 330 MPa . In the welded state, the joints ruptured along the interface layer. After heat treatment, the joints were quasi-cleavage fractures. The fracture sites were located on the side of the TiAl alloy and about 1 mm away from the interface layer.