脉冲电流冲击处理对TC11钛合金组织与性能的影响

利用光学显微镜、扫描电镜、X射线衍射仪、万能材料试验机和显微硬度计等研究了脉冲电流冲击处理(EST)对TC11钛合金微观组织和力学性能的影响。结果表明:不同脉冲数对TC11钛合金微观组织中α相的比例、β转变组织的板条尺寸和残余压应力大小影响明显,随EST脉冲数的提升,α相含量及板条状β转变组织中次生α相含量呈现先增加后减少的趋势。经最佳工艺参数(900 A、50 Hz、25个脉冲)脉冲电流冲击处理后,TC11钛合金中α相细小均匀,β转变组织板条长度、厚度和间距较处理前试样分别减小了51.9%、58.0%和36.8%,此时合金力学性能提升最为明显:伸长率提高了12.7%,显微硬度增加了4.7%,残余压应力增加48.4%。

Effect of electropulse shocking treatment on microstructure and properties of TC11 titanium alloy

Effect of electropulse shocking treatment(EST) on microstructure and mechanical properties of TC11 titanium alloy was studied by means of metallographic microscope, scanning electron microscope, X-ray diffractometer, universal material testing machine and microhardness tester. The results show that the ratio of α phase in the microstructure of TC11 titanium alloy, the lath size of β transformation structure and residual compressive stress are significantly affected by different pulse numbers. With the increase of EST pulse number, the content of α phase and the content of secondary α phase in lath like β transformation structure increase firstly and then decrease. After treated by the ETC with the best process parameters (900 A, 50 Hz, 25 pulses), the α phase in the TC11 titanium alloy is fine and uniform, and the length, thickness and spacing of β transformation lath are reduced by 51.9%, 58.0% and 36.8%, respectively, compared with those before treatment. At this time, the mechanical properties of TC11 titanium alloy are improved most obviously: elongation increased by 12.7%, microhardness increased by 4.7%, and residual compressive stress increased by 48.4%.