CMT+P过程及后热处理对TC4钛合金增材构件组织和性能影响

Effects of CMT+P process and post heat treatment on microstructure and properties of TC4 component by additive manufacturing

关键词:  显微组织  热处理  增材制造  钛合金

Key words:  microstructure  heat treatment  additive manufacturing  titanium alloy

摘要:

采用CMT+P程序进行TC4钛合金焊丝电弧增材制造，针对增材过程中热积累造成的组织性能不均匀性，采用两种不同热处理工艺以期改善这种不均匀性，并提高增材构件性能. 结果表明，采用CMT+P进行增材制造可以获得成形良好的沉积零件，当送丝速度为6 m/min，焊枪行走速度为0.3 m/min时，其热输入为313 J/mm， 沉积零件显微组织从上至下不断粗大. 热处理后试样不同部位晶粒大小变得均匀，抵抗塑性变形的能力增强. 拉伸试验表明，在600℃，4 h热处理条件下，构件的抗拉强度最高，为1 124 MPa. 断口分析表明， 所有试样断裂方式均为韧性断裂.

Abstract:

CMT + P procedure was used in wire and arc additive manufacturing of TC4 titanium alloy. Aiming at inhomogeneity in microstructure and properties by heat accumulation in addictive manufacturing process, two heat treatment processes were used to improve the inhomogeneity and promote the performance of component by addictive manufacturing. The results showed that the as-built wall in a good appearance can be obtained with CMT+P procedure. When the wire feeding speed is 6 m/min and the welding torch speed is 0.3 m/min, the heat input is 313 J/mm, and the microstructure of as-built wall is continuously growing from bottom to top. The grain size for different positions of sample becomes uniform and the resistance to plastic deformation for the sample is enhanced after heat treatment. Tensile testing shows that the component has the highest tensile strength of 1 124 MPa under 600℃ and 4 h condition. The fracture analysis shows that all the fracture modes are ductile fracture.