(1. 湖南科技大學(xué) 機電工程學(xué)院，湘潭 411201；
2. 中南大學(xué) 材料科學(xué)與工程學(xué)院，長沙 410083；
3. 重慶大學(xué) 國家鎂合金工程技術(shù)中心，重慶 400044)
摘 要: 對擠壓態(tài)AZ31鎂合金試樣沿擠壓方向截取試樣(0°試樣)和垂直于擠壓方向截取試樣(90°試樣)，并分別進(jìn)行變形量為12%的冷鍛變形，在320 ℃下保溫不同時間進(jìn)行再結(jié)晶退火。利用金相顯微鏡和背散射電子衍射技術(shù)研究AZ31鎂合金的微觀組織演變。結(jié)果表明：經(jīng)冷鍛變形的0°試樣，內(nèi)部存在大量細(xì)小碎晶、{ }-{ }、{ }和{ }-{ }等孿晶，平均小角度取向差頻率為0.031，硬度由57HV增至71.3HV，隨后的再結(jié)晶退火可顯著細(xì)化原始混晶組織；經(jīng)冷鍛變形的90°試樣，內(nèi)部含有少量的{ }-{ }二次孿晶，平均小角度取向差頻率為0.017，硬度由57HV增至69.3HV，再結(jié)晶退火時，與0°試樣對比，靜態(tài)再結(jié)晶開始及結(jié)束時間均被推遲。
關(guān)鍵字: AZ31鎂合金；冷鍛；靜態(tài)再結(jié)晶；織構(gòu)
（1. College of Electromechanical Engineering, Hunan University of Science and Technology, Xiangtan 411201, China;
2. School of Materials Science and Engineering, Central South University, Changsha 410083, China;
3. National Engineering Research Center for Magnesium Alloys, Chongqing University, Chongqing 400044, China）
Abstract:0 ° and 90° samples of extruded AZ31 magnesium alloys were obtained from cutting along the extrusion direction and perpendicular to the extrusion direction, respectively, and 12% cold forging deformation was carried out on them, then recrystallization annealing tests were performed at 320℃ for different durations. The microstructure evolution of AZ31 magnesium alloys was investigated by metalloscopy and electron backscatter diffractometry. The results show that in 0° sample there are a large amount of tinny broken grains, { }-{ }, { } and { }-{ }, the average frequency of low angle grain boundary is 0.031, and the hardness increases from 57HV to 71.3HV. Besides, original mischcrystal structure can be refined obviously by subsequent recrystallization annealing. As for 90° sample, only a few of { }-{ } double twins come out, the average frequency of low angle grain boundary is 0.017, and the hardness increases from 57HV to 69.3HV. By comparison with that of 0° sample, the starting and ending times of static recrystallization for 90° sample are delayed during the recrystallization annealing process.
Key words: AZ31 magnesium alloy; cold forging; static recrystallization; texture
