电弧沉积制造TC4钛合金的组织和力学性能研究

Study on Microstructure and Mechanical Properties of Arc Deposition Manufactured TC4 Titanium Alloy

利用钨极氩弧沉积制造技术制备了TC4钛合金试样,研究了电弧沉积制造TC4钛合金的显微组织和力学性能。分析表明:电弧沉积制造TC4钛合金组织宏观上呈以基材为基底的外延连续生长的粗大柱状晶特点,由α相和β相组成,但α相随位置的不同形貌有差别,在上部位置呈粗大针状魏氏体组织,在中部呈粗化了的层片状网篮组织,在下部呈针状+层片状混合组织。显微硬度测试表明:沉积成形件硬度较高,且越靠近试样表面硬度越大。室温拉伸测试显示,沉积态试样具有明显的各向异性特点,沿焊接水平方向拉伸强度较高,沿沉积高度方向拉伸塑性较好,且所有测试试样均具有超过锻造TC4合金的强度和塑性指标。

TC4 titanium alloy block was prepared by arc deposition manufactured （ADM） method. The microstructure and mechanical properties of the alloy were investigated. The analysis results show that the microstructure of ADMed TC4 titanium alloy sample consists of coarse columnar grains epitaxially growing from the substrate, α and β phases are detected by XRD analysis. The morphology of α phase changes at different locations, i.e. widmanstatten structure with needle-like α phase at upper part, basket-weave structure with coarse tabular α phase at middle part and a mix structure of needle-like and tabular α phase at lower part. The microstructure measurement shows that a higher hardness exists in the ADMed material compared with the substrate and it decreases as far from the surface of the sample. An anisotropic tensile property is discovered and the tensile strength along the welding direction is better than that when tested along the deposition direction, which is contrary to the ductility of the sample. All the tested samples show a better tensile property compared with the forged materials.