(1. 中南大學材料科學與工程學院，長沙 410083；
2. 中南大學材料科學與工程學院有色金屬材料科學與工程教育部重點實驗室，長沙 410083)
摘 要: 通過光學顯微鏡(OM)及電子背散射衍射分析技術(EBSD)研究室溫多向鍛壓(MDF)下AZ31鎂合金在473 K下的靜態(tài)再結晶(SRX)行為，對高密度孿晶組織的再結晶行為、顯微組織演變、再結晶動力學及退火初期再結晶晶粒取向進行研究。結果表明：室溫多向鍛壓AZ31鎂合金的累積應變量越大，孿晶密度越高，退火過程中越容易發(fā)生再結晶。不管試樣累積應變量高還是低，硬度曲線在退火過程中均分為3個階段，且第一階段硬度值均基本不變，但低累積應變量試樣比高累積應變量試樣更遲進入第二階段，進入第三階段低累積應變量試樣硬度繼續(xù)呈下降趨勢而高累積應變量試樣硬度基本處于穩(wěn)態(tài)。高累積應變量試樣能用JMAK方程很好地描述退火組織的再結晶過程，但低累積應變量試樣卻不能。退火初期，再結晶晶粒與母相仍然保持孿晶關系，且其基面取向與最終壓縮方向垂直或平行。
關鍵字: AZ31鎂合金；孿晶；靜態(tài)再結晶；再結晶動力學；晶粒取向
（1. School of Materials Science and Engineering, Central South University, Changsha 410083, China;
2. Key Laboratory of Nonferrous Materials Science and Engineering,
Ministry of Education, Central South University, Changsha 410083, China）
Abstract:Static recrystallization (SRX) behavior of a wrought AZ31 magnesium alloy at 473 K was studied after multi-directional forging (MDF) using optical microscopy (OM) and electron backscattering microscopy (EBSD). Effects of introduced high-density twins on SRX behavior, microstructural development, SRX kinetics and initial orientation of SRX grains during the isothermal annealing were investigated. The results show that SRX can be accelerated through high-density twins introduced by high cumulative strain. The variation of hardness (HV) with annealing time of wrought samples includes three periods irrespective of prior strain: HV hardly changes in the early stage of annealing and drops rapidly in the middle stage until it finally approaches the fully annealed value. At high cumulative strain, variation of HV proceeds earlier into the middle stage and then reaches a steady value while HV keeps dropping gradually in the final stage at low cumulative strain. The relationship between recrystallization volume fraction and annealing time can be perfectly described by JMAK equation at high cumulative strain but cannot at low cumulative strain. SRX grains exhibit almost same orientations of prior twins with its basal plane aligned parallel and perpendicular to the forging direction of the last pass.
Key words: AZ31 magnesium alloy; twin; static recrystallization; recrystallization kinetics; grain orientation
