(1. 中南大學(xué) 材料科學(xué)與工程學(xué)院，長沙 410083；
2. 中南大學(xué) 有色金屬材料科學(xué)與工程教育部重點實驗室，長沙 410083)
摘 要: 研究了高溫條件下Mg-Gd-Y-Zr 合金形變孿生變體的選擇規(guī)律。在350 ℃及真應(yīng)變?yōu)?.05時通過單向壓縮鑄態(tài)Mg-Gd-Y-Zr合金試樣，獲得形變孿生組織。利用背散射電子衍射(EBSD)技術(shù)與透射電子顯微鏡(TEM)確定孿生類型為{ } 孿生。通過對比EBSD測試結(jié)果與理論計算結(jié)果，確定了孿生變體。采用Schmid因子準則與Taylor準則分析了{ } 孿生發(fā)生的規(guī)律。結(jié)果表明：Schmid因子準則僅僅考慮孿生變體的Schmid因子，其預(yù)測結(jié)果與實驗結(jié)果不符；而Taylor準則考慮了孿生、基面滑移與非基面滑移的相互協(xié)調(diào)作用，可準確預(yù)測{ }孿生的變體選擇結(jié)果；稀土鎂合金的高溫形變也需要孿生參與協(xié)調(diào)塑性變形。
關(guān)鍵字: 鎂合金；形變孿生；Schmid 因子；Taylor準則
elevated temperature in Mg-RE alloy
（1. School of Materials Science and Engineering, Central South University, Changsha 410083, China;
2. Key Laboratory of Nonferrous Metal Materials Science and Engineering, Ministry of Education, Central South University, Changsha 410083, China）
Abstract:The selection law of deformation twinning variants at elevated temperature in Mg-Gd-Y-Zr alloy was investigated. The microstructures containing deformation twins were prepared by compressing as-cast Mg-Gd-Y-Zr alloy at 350 ℃ and low true strain of 0.05. The observed { } twins were characterized by electron backscatter diffractometry (EBSD) and transmission electron microscopy (TEM). Comparison between EBSD analysis and theoretical calculation was conducted to identify the twinning variants. Two methods, Schmid factor and Taylor criterion, were used to analyze the law for occurrence of twinning variants. The results reveal that Schmid factor fails to predict the activated twinning variants, while Taylor criterion allows the experimental observations to be readily predicted considering { } twins, basal slip and non-basal slips. For Mg-Re alloy, deformation twinning at elevated temperature is still necessary to accommodate the plastic strain along with dislocation slip.
Key words: magnesium alloy; deformation twins; Schmid factor; Taylor criterion
