SiCp/2024与2219铝合金电子束焊接

Electron beam welding of SiCp/2024 and 2219 aluminium alloy

关键词:  SiC_p/2024铝基复合材料  2219铝合金  电子束焊接  接头组织  力学性能

Key words:  SiC_p/2024 matrix composite  2219 aluminium alloy  electron beam welding  microstructure  mechanical properties

摘要:

分别采用电子束对中焊、偏束焊技术,研究了SiC颗粒增强铝基复合材料SiC_p/2024与2219铝合金的接头组织及力学性能. 结果表明,对中焊时接头易出现SiC增强相的偏聚,同时发生严重的界面反应,生成大量脆性相Al₄C₃,接头抗拉强度最高为104 MPa. 采用偏束焊工艺可以很好地抑制界面反应,通常只在焊缝上部与SiC_p/Al热影响区上部生成少量脆性相Al₄C₃,接头抗拉强度最高可达131 MPa. 试件均断裂在母材界面反应层上,且为明显的脆性断裂. 不同工艺下接头横截面硬度分布存在突变区,该区域在SiC_p/2024熔合区附近,该处脆性相Al₄C₃的生成导致硬度升高.

Abstract:

SiC_p/2024 matrix composites reinforced with SiC particles and 2219 aluminium alloy were joined by centered electron beam welding and deflection beam welding, respectively, and the microstructures and mechanical properties of these joints were studied. The results show that SiC particles were more likely to segregate by centered electron beam welding, meanwhile lots of Al₄C₃ brittle intermetallic compounds formed for serious interface reactions. Moreover, the tensile strength of the joints was about 104 MPa. The interface reaction was restrained by choosing deflection electron beam welding,and there was a little Al₄C₃ intermetallic compounds formed at the top of the joint and heat affected zone of SiC_p/Al. The quasi-cleavage fracture occurred at the interface reaction layer of the base metal. There was a hardness transition zone near the SiC_p/2024 fusion zone for both methods. The brittle intermetallic compounds Al₄C₃ formed in this zone results in the high hardness.