(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) 有色金屬先進(jìn)結(jié)構(gòu)材料與制造協(xié)同創(chuàng)新中心，長沙 410083；
3. 中南大學(xué) 有色金屬材料科學(xué)與工程教育部重點(diǎn)實(shí)驗(yàn)室，長沙 410083)
摘 要: 結(jié)合光學(xué)顯微鏡(OM)、電子背散射衍射技術(shù)(EBSD)等，研究分步鍛壓對AZ91鎂合金變形過程中組織演化及性能的影響。采用室溫拉伸實(shí)驗(yàn)檢測分步鍛后樣品的力學(xué)性能，并將分步鍛后樣品的組織、性能同普通一步鍛壓工藝樣品的進(jìn)行了比較。結(jié)果表明：分步鍛壓工藝可有效促進(jìn)動(dòng)態(tài)再結(jié)晶的發(fā)生，鍛壓過程中流變應(yīng)力明顯降低，鍛后組織細(xì)化效果明顯，變形織構(gòu)弱化，綜合力學(xué)性能提升。在623 K下分步鍛壓后，樣品的再結(jié)晶體積分?jǐn)?shù)升高至95%，在保持高強(qiáng)度的同時(shí)，鍛后樣品的室溫伸長率達(dá)到19.6%，與相同溫度普通一步鍛壓后的樣品相比提升了約53%。
關(guān)鍵字: AZ91鎂合金；分步鍛壓；動(dòng)態(tài)再結(jié)晶；力學(xué)性能
（1. School of Materials Science and Engineering, Central South University, Changsha 410083, China;
2. Nonferrous Metal Oriented Advanced Structural Materials and Manufacturing Cooperative Innovation Center, Central South University, Changsha 410083, China;
3. Key Laboratory of Nonferrous Materials Science and Engineering, Ministry of Education, Central South University, Changsha 410083, China）
Abstract:The effects of interrupted forging on the microstructural evolution of a cast AZ91 magnesium alloy were investigated by optical microscopy (OM) and electron back-scattering diffractometry (EBSD) and resultant mechanical properties were detected through tensile tests at ambient temperature. The results show that dynamic recrystallization (DRX) is remarkably accelerated and a decreased flow stress is observed under the condition of interrupted forging. Accordingly, there is an obvious grain refinement and the basal texture is weakened after interrupted forging, resulting in an improvement in mechanical property. As the volume fraction of dynamic recrystallized grains increases from 47% to 95% after interrupted forging at 623 K, the ambient tensile elongation of deformed sample increases by 53%, reaching the maximum of 19.6%, with little or no drop in strength.
Key words: AZ91 Mg alloy; interrupted forging; dynamic recrystallization; mechanical properties
