摘要
对3.5 mm厚的C18000铜合金板进行搅拌摩擦焊焊接试验.在焊接速度120 mm/min,转速1 200 r/min工艺下获得无缺陷焊接接头.在金相显微镜下对接头的宏观形貌、微观组织进行观察,用扫描电镜和透射电镜对母材和搅拌区组织进行观察分析.结果表明,接头区大致分为母材区、热影响区、热力影响区和搅拌区,搅拌区晶粒细小均匀,热力影响区晶粒沿边界切线方向被拉长;搅拌区Cr3Si相部分溶解,搅拌区组织中的Cr单质相和Ni2Si相溶解导致接头硬度和抗拉强度下降.搅拌区平均硬度为151.4 HV;接头抗拉强度为497 MPa,达到母材的72%;接头电导率下降为35%IACS.
C18000 copper alloy plate with thickness of 3.5 mm was subjected to friction stir welding experiment.Sound welded joints were obtained under the welding speed of120 mm/min and the rotation speed of 1 200 r/min. The macromorphology and micro-structure of the joint were observed under metallographic microscope, and the microstructure of the base metal and stirring zone were observed and analyzed by scanning electron microscopy and transmission electron microscopy. The results showed that the joint zone could be generally divided into the base metal(BM), the heat affected zone(HAZ), the thermo-mechanically affected zone(TMAZ)and the stir zone(SZ). The grain in SZ was small and welldistributed, and the grain in TMAZ was elongated along the tangential direction of the boundary. It was found that the particles were Cr3 Si phase, and it was dissolved in the stirring zone. The Cr element phase and Ni2 Si phase dissolved in the microstructure of SZ, which resulted in a decrease in joint hardness and tensile strength. The average hardness of the SZ was 151. 4 HV; the tensile strength of the joint was 497 MPa,which was 72% of the BM. The conductivity of the joint dropped to 35% IACS.
引文
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