葛佳琪,杨文朋,王诗蒙,崔红保,郭学锋.纯镁在ECAP中组织演变及温度对变形组织的影响[J].有色金属工程,2019,9(9):.
纯镁在ECAP中组织演变及温度对变形组织的影响
Microstructure Evolution of Pure Magnesium in ECAP and Effect of temperature on deformed microstructure
投稿时间:2018-09-09  修订日期:2018-09-25
DOI:
中文关键词:  纯镁 等通道转角挤压 组织 动态再结晶
英文关键词:pure mg  equal channel angular pressing  microstructure  dynamic recrystallization
基金项目:国家自然科学基金;河南理工大学博士基金;河南省矿业工程重点实验室开放基金
              
作者单位
葛佳琪 河南理工大学 材料科学与工程学院
杨文朋 河南理工大学 材料科学与工程学院
王诗蒙 河南理工大学 材料科学与工程学院
崔红保 河南理工大学 材料科学与工程学院
郭学锋 河南理工大学 材料科学与工程学院
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中文摘要:
      利用等通道转角挤压(ECAP)对纯镁在200~300 ℃进行挤压,使用光学显微镜和透射电镜研究不同温度下组织特征以及相同温度不同区域的组织特征,结果表明:晶粒尺寸由应变速率和温度决定,经200 ℃挤压后晶粒最细,平均晶粒尺寸约25.6 μm。经225 ℃挤压1/2道次后,剪切变形前组织主要为长条状的粗大晶粒,粗晶中伴有孪晶产生;剪切区的组织主要为剪切变形带和大量的细晶围绕在粗晶周围;剪切变形后组织主要为再结晶组织和少量长条状粗晶。纯镁在225 ℃挤压后晶粒内部存在较多的基面位错,同时也存在?c a?非基面位错。低温ECAP挤压时,再结晶方式为非连续动态再结晶和孪晶动态再结晶共同作用,高温变形时以非连续动态再结晶为主。
英文摘要:
      Equal channel angular pressing (ECAP) was performed on pure Mg at the temperature range of 200~300 ℃.The microstructure evolution of pure mg during ECAP process were investigated by optical microscopy(OM) and transmission electron microscopy(TEM).The results show that the recrystallized grain size is determined by strain rate and temperature, a minimum grain size of 25.6 μm is obtained at 200 ℃.After 1/2 pass of ECAP process at 225 ℃, the microstructure prior to shear deformation is consisted of long strips coarse grains and twins. The microstructure in the shear zone is mainly shear bands and a large amount of fine grains surrounding the coarse grains. After shear deformation, the microstructure is mainly dynamic recrystallized grains and a small amount of long strips coarse grains. Large amount of basal dislocations are found in the sample, and there are also a small number of non-basal dislocations. At low temperatures ECAP, the dynamic recrystallization mode is comprehensive effect of discontinuous dynamic recrystallization and twinning dynamic recrystallization. With the temperature increasing, the dynamic recrystallization mode turns into discontinuous dynamic recrystallization.
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