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采用组织观察、性能检测、断口分析等方法研究了脉冲电流对Ti-6Al-4V合金显微组织及力学性能的影响。结果表明,脉冲电流使试样瞬间急速升温、产生较高的热压应力,并发生α→β相变,随后试样快速降温冷却发生β→α′相变。由于急速升温和快速冷却,新相的形核率增加且无充足时间长大,使合金的显微组织细化,而相变和组织细化导致了合金力学性能提高和电阻率变化。适当优化电脉冲处理工艺参数可使Ti-6Al-4V合金的综合力学性能明显提高。通过测量电阻变化可间接表征电脉冲处理后材料微观组织结构的变化程度。
The effects of pulse current on the microstructure and mechanical properties of Ti-6Al-4V alloy were investigated by means of microstructure observation, performance test and fracture analysis. The results show that the pulse current rapidly heats the sample instantaneously, resulting in higher hot compressive stress and α → β phase transformation, followed by rapid β → α ’phase transformation. Due to rapid heating and rapid cooling, the nucleation rate of the new phase increases without enough time to grow, so that the microstructure of the alloy is refined, and the phase transformation and refinement of the microstructure lead to the improvement of the mechanical properties and the change of the resistivity of the alloy. Appropriate optimization of electrical pulse processing parameters Ti-6Al-4V alloy mechanical properties significantly improved. By measuring the resistance change, the degree of change of the microstructure of the material after the electrical pulse treatment can be indirectly characterized.