焊后热处理对2A14高强铝合金电子束焊接头组织及力学性能的影响
Effects of Post Weld Heat Treatment on Microstructure and Mechanical Properties of 2A14 High Strength Aluminum Alloy by Electron Beam Welding
王亚荣 1黄文荣 1雷华东1
作者信息
- 1. 中国工程物理研究院机械制造工艺研究所 绵阳621900
- 折叠
摘要
轻质化的需求使得人们把关注的焦点集中于轻质材料,高强铝合金作为钢结构材料的最佳替代品,受到越来越广泛的关注,利用电子束焊接高强铝合金,为获得性能优良的2A14高强铝合金电子束焊接接头,采用焊后热处理,通过组织观察(光学显微镜和扫描电镜)、维氏硬度测试、接头拉伸性能测试等方法研究焊后热处理对2A14电子束焊接接头显微组织和性能的影响.结果表明,通过焊后热处理,焊缝中心原晶界分布的网状共晶组织回溶于基体组织中消失,焊缝内部析出大量弥散强化项,基体强化效果增强,显微硬度显著升高,由焊态下低子母材硬度直接升高至超过母材硬度.接头抗拉强度由原来的355MPa提高到465 MPa,超过了母材强度.接头断裂均发生在焊缝,由断口分析发现热处理后接头韧性增强,韧窝深度增加,且有第二相质点出现.
Abstract
The challenges of significant weight reduction have promoted a focus on selection of light-weight materials. That is the reason that high strength aluminum alloy is becoming widely recognized as the candidates to replace steel. In order to develop proper post weld heat treatment process of 2A14 high strength aluminum alloy welded by electron beam, the effects of post weld heat treatment on microstructure and mechanical properties of 2A14 aluminum alloy welded joint are studied by using optical microscope (OM), scanning electron microscope (SEM), hardness test and tensile test. The results showed that the eutectic structure of the grain-boundary dissolved into the matrix gradually, dispersion-strengthening phase precipitated in weld zone and the hardness of weld seam increased obviously after post weld heat treatment. The tensile strength of the weld seam increased from 3SS Mpa to 465 Mpa, even larger than the base metal. The fracture analysis show the dimples became deeper and the fracture location is all in weld seam, which proposes that the toughness of the weld increased.
关键词
高强铝合金/电子束焊/热处理/组织/力学性能Key words
High strength aluminum alloy/Electron beam welding/Heat treatment/Microstructure/Mechanical properties引用本文复制引用
出版年
2011
NETL
NSTL
维普
万方数据