AZ31B镁合金/PRO500超高强度钢TIG熔钎连接界面反应特性及力学性能

Interfacial Reaction Characteristics and Mechanical Properties of Welding-brazing Bonding Between AZ31B Magnesium Alloy and PRO500 Ultra-high Strength Steel

利用TIG电弧作为热源开展AZ31B镁合金与超高强度钢PRO500熔钎连接实验,研究界面反应特性及力学性能。结果表明:AZ31B镁合金/PRO500钢能够利用TIG电弧熔钎焊实现有效连接;接头界面中各基体元素的氧化具有强烈的热力学自发性并在接头界面中形成氧化物聚集且包含AlFe3相的过渡区,其硬度介于两种基材之间;界面中靠近钎接位置的钢基体在焊接热循环作用下会出现回火软化现象;大的焊接热输入会导致界面过渡区中脆性化合物相增多,结合强度显著下降。

Experiments were carried out with TIG welding-brazing of AZ31B magnesium alloy to PRO500 steel using TIG arc as heat source. The interfacial reaction characteristics and mechanical properties of the welding-brazing bonding were investigated. The results show that an effective bond-ing is achieved between AZ31B magnesium alloy and PRO500 steel by using TIG welding-brazing method. Some spontaneous oxidation reactions result in the formation of a transition zone containing AlFe3 phase with rich oxide. The micro-hardness value of the interfacial transition zone is between that of the AZ31B and the PRO500. Temper softening zone appears due to the welding thermal cycle nearby the bonding position in the interface. A higher heat input makes an increase of the brittle pha-ses and leads to an obvious decrease of the bonding strength.