钛合金/铜-镍/不锈钢焊接接头的组织与性能

Microstructure and properties of titanium alloy/coppernickel/stainless steel welded joints

采用铜-镍复合填充金属进行了钛合金和不锈钢的冷金属过渡焊接,借助扫描电子显微镜、X射线衍射仪研究铜-镍复合填充金属对钛合金/不锈钢焊接接头微观组织和力学性能的影响.结果表明,添加铜-镍复合填充金属后得到了无焊接缺陷的钛合金/不锈钢焊接接头.接头中形成了硬度相对Ti-Fe,Ti-Cu金属间化合物较低的Ti-Ni金属间化合物,改善了钛合金/不锈钢焊接接头的拉伸性能.当焊接电流为182 A时,钛合金/不锈钢接头的拉剪强度最大为348 MPa.钛合金/不锈钢接头由不锈钢-焊缝金属界面、不锈钢-纯镍-钛合金界面、钛合金-焊缝金属界面和焊缝金属组成,接头中形成了Ti-Cu,Ti-Ni,Al-Cu-Ti和Al-Ni-Ti-Fe-Cu金属间化合物.随着焊接电流的增大,钛合金侧界面反应层的显微硬度逐渐增大,且反应层的宽度也逐渐变宽.创新点:研究铜-镍复合填充金属对Ti-6Al-4V(TC4)钛合金/304不锈钢焊接接头的微观组织、化合物组成以及力学性能的影响.

Cold metal transfer welding of titanium alloy and stainless steel was carried out using copper-nickel composite filler metal.The effects of copper-nickel composite filler metal on the microstructure and mechanical properties of the joint were investigated by scanning electron microscope and X-ray diffractometer.The results show that defect-free welded joint was obtained,and Ti-Ni intermetallic compound was formed in the joint.As the hardness of the Ti-Ni intermetallic compound is lower than that of the Ti-Fe and Ti-Cu intermetallic compounds,the tensile property of the joint was improved.When the welding current was set at 182 A,the maximum tensile and shear strength of the joint was achieved at 348 MPa.The titanium alloy/stainless steel joint was composed of stainless steel-weld metal interface,stainless steel-pure nickel-titanium alloy interface,titanium alloy-weld metal interface and weld metal,and Ti-Cu,Ti-Ni,Al-Cu-Ti and Al-Ni-Ti-Fe-Cu intermetallic compounds were formed in the joint.With the increase of welding current,there was a gradual growth in the microhardness and the width of the interface reaction layer on the titanium alloy side.Highlights:The effects of copper-nickel composite filler metal on the microstructure,compound composition and mechanical properties of Ti-6Al-4V(TC4)titanium alloy/304 stainless steel welded joint were investigated.