脉冲电流对再制造毛坯裂纹尖端组织及性能的影响  

Effects of Pulsed Current on Microstructure and Properties of Crack Tip in Remanufacturing Blank

作　　者：邓德伟[1,2] 刘倩倩[1] 李晓娜[1] 于涛[3] 张林[2] 王罡[4] 张洪潮[3] 

机构地区：[1]大连理工大学材料科学与工程学院,辽宁大连116023 [2]沈阳鼓风机集团股份有限公司,辽宁沈阳110869 [3]大连理工大学机械工程学院,辽宁大连116023 [4]清华大学,北京100084

出　　处：《稀有金属材料与工程》2017年第8期2208-2213,共6页Rare Metal Materials and Engineering

基　　金：国家重点基础研究发展计划("973"计划)(2011CB013402);辽宁省自然科学基金(2014028002);辽宁省科技创新重大专项(201303002);沈鼓-大工重大科研发展基金;中央高校基本科研业务费专项资金

摘　　要：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。A high energy pulsed current impacting device was used to treat 316 austenitic stainless steel containing prefabricated unilateral fatigue crack aiming for remanufacturing. The influence of high density pulsed current on the microstructure at crack tip was investigated by metallographic microscope, X-ray diffraction, electron backscattered diffraction（EBSD） and transmission electron microscope（TEM）. And the evolution of microstructure during melting treatment was analyzed. Results show that the structure at crack tip is obviously refined after the pulsed current processing, and the gradient structure including the columnar crystal area, recrystallization zone and matrix is observed. Due to the rapid heating and cooling, the generation of high-speed electronic wind and electrically induced plasticity effect reduce the thermodynamic barrier of recrystallization or phase change. Thus, the rate of nucleation is increased, and the grain growth process is inhibited. Therefore the grain size of recrystallization zone is smaller than that of the matrix, and hence the mechanical properties of materials are improved.

关 键 词：再制造 脉冲电流 再结晶 组织细化 

分 类 号：TG142.71[一般工业技术—材料科学与工程]