Zn-Mg钎料钎焊镁合金AZ31B的显微组织与力学性能

Microstructure and mechanical properties of magnesium alloy AZ31B solder joint using Zn-Mg filler metal

关键词:  AZ31B  Zn-Mg钎料  感应钎焊  共析组织  接头强度

Key words:  AZ31B  Zn-Mg filler metal  induction soldering  eutectoid structure  joint strength

摘要:

为了连接变形镁合金AZ31B母材,以Zn-Mg钎料对变形镁合金AZ31B进行了高频感应钎焊,研究了Zn-Mg钎料的显微组织、钎焊接头的显微组织及力学性能.采用X射线衍射仪、扫描电镜、X射线能谱分析仪等分析了钎焊接头的界面组织及钎缝物相,测试了钎焊接头的强度及界面组织的显微硬度.结果表明,Zn-Mg钎料与母材AZ31B发生强烈合金反应在钎缝中生成α-Mg基体和α-Mg+γ-MgZn共析组织,Zn-Mg钎料的原始显微组织消失.钎焊接头中α-Mg+γ-MgZn共析组织的显微硬度最高,钎焊对接接头平均抗拉强度为51 MPa,钎焊搭接接头平均抗剪强度达到36 MPa.钎焊接头的断裂形式为沿晶脆性断裂,断裂主要发生在α-Mg+γ-MgZn共析组织处.

Abstract:

In order to join wrought magnesium alloy AZ31B sheet high-frequency induction soldering of wrought magnesium alloy AZ31B using Zn-Mg filler metal was investigated. The microstructure of the Zn-Mg filler metal was evaluated. Both the interface microstructure and the mechanical properties of the solder joint were studied. The interface microstructure and formation phases of the soldering seam were investigated by X-ray diffractometer, scanning electron microscopy and X-ray energy dispersive spectrometer. The strength of the solder joint and the microhardness of the interface microstructure were tested. The results show that Zn-Mg filler metal reacts with the base metal AZ31B, and α-Mg matrix and α-Mg +γ-MgZn eutectoid structure are formed in soldering seam, and the microstructure in the original Zn-Mg filler metal disappearing after the soldering process. The average tensile strength of the butt joint is 51 MPa and the average shear strength of the overlap joint is 36 MPa. The microhardness of the α-Mg +γ-MgZn eutectoid structure is the maximum in the solder joint. The fracture morphology of the solder joint exhibits intergranular fracture mode and the fracture comes from α-Mg +γ-MgZn eutectoid structure.