采用冷喷涂铜涂层做中间层的镁合金与钢共晶接触反应钎焊工艺及接头性能

采用厚度为50 μm的冷喷涂铜涂层作为中间层，研究了连接温度和保温时间对AZ31B镁合金/钢异种金属接触反应钎焊接头剪切强度的影响规律.通过金相显微镜、扫描电镜（SEM）、X射线衍射仪（XRD）、显微硬度和剪切强度试验，研究了AZ31B镁合金/钢钎焊接头界面微观组织和力学性能.结果表明，当连接温度为530℃，保温时间为60 min时，接头剪切强度达到最大值36.9 MPa.AZ31B镁合金/钢钎焊接头界面反应产物主要为Mg₂Cu，α-Mg固溶体和Mg-Cu-Al三元相.Mg-Cu-Al三元相的尺寸和分布，以及08F钢侧是否存在Mg₂Cu共晶相共同决定了接头的强度.由钎焊接头断口可知，最佳工艺参数下断裂方式为脆性断裂与韧性断裂的混合方式.

Contact reaction brazing of magnesium alloy to steel using cold-spraying deposited copper coating as interlayer

Contact Reaction Brazing (CRB) of AZ31B magnesium alloy to 08F steel was performed using cold-spraying deposited copper coating, with thickness of 50 μm, as interlayer. The influence of bonding temperature and dwell time was investigated and discussed. The microstructure and mechanical properties of brazed joints were examined with optical microscopy, Scanning Electron Microscope (SEM), X-Ray Diffraction (XRD), tensile test and microhardness test. The results show that the maximum shear strength of 36.9 MPa was obtained for the specimens brazed at 530℃ for 60 minutes under pressure of 0.05 MPa. The reaction interface of brazed AZ31B/Cu coating/08F steel joint was mainly composed of Mg₂Cu, α-Mg solid solution and Mg-Cu-Al ternary phases. The size and distribution of brittle Mg-Cu-Al intermetallic phase and the existence of Mg₂Cu eutectic phase on 08F steel side were responsible for the properties of brazed joints. The fracture surface exhibited a mixed fracture mode of brittle fracture and ductile fracture under the optimal parameters.