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以再制造为目标,利用高能脉冲电流冲击装置对含有单边裂纹的316奥氏体不锈钢进行脉冲电流处理。采用金相显微镜、X-射线衍射仪、电子背散射衍射(EBSD)、透射电子显微镜(TEM)等表征手段,研究高密度脉冲电流对裂纹尖端区域微观组织与结构的影响,分析裂纹尖端组织加热熔化及热处理时的组织演变过程。结果表明:脉冲电流处理后,裂纹尖端组织发生了明显细化并出现组织梯度,包括柱状晶区、再结晶区及基体区。脉冲电流的快速加热和快速冷却、高速电子风的产生、电致塑性等作用降低了再结晶或相变时的热力学屏障,提高了形核率,抑制了晶粒长大过程,获得了比原始晶粒尺寸小的再结晶晶粒,材料的力学性能得到提高。
To remanufacture as the goal, the use of high-energy pulse current impact device on 316 austenitic stainless steel with unilateral crack pulse current processing. The effects of high-density pulse current on the microstructure and structure of crack tip region were studied by means of metallographic microscope, X-ray diffraction, electron backscatter diffraction (EBSD) and transmission electron microscopy (TEM) The process of tissue evolution during melting and heat treatment. The results show that after the pulse current treatment, the crack tip microstructure has been obviously refined and the gradient of microstructure appears, including columnar zone, recrystallized zone and matrix zone. The rapid heating and rapid cooling of pulsed current, the generation of high-speed electron wind, the electrical plasticity, etc. reduce the thermodynamic barrier during recrystallization or phase transformation, improve the nucleation rate, inhibit the grain growth process, The grain size of the recrystallized grains, the mechanical properties of the material is improved.