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AZ31B镁合金薄板热拉伸显微组织试验研究
引用本文:杨东峰,董国疆,赵长财,郝海滨.AZ31B镁合金薄板热拉伸显微组织试验研究[J].塑性工程学报,2011,18(2).
作者姓名:杨东峰  董国疆  赵长财  郝海滨
作者单位:1. 燕山大学车辆与能源学院,秦皇岛,066004
2. 燕山大学机械工程学院,秦皇岛,066004
基金项目:国家自然科学基金资助项目
摘    要:采用Gleeble-3500热模拟试验机、金相显微镜和扫描电镜,研究AZ31B镁合金在不同变形条件下的微观组织和断口形貌特点,并且研究了该合金在不同变形条件下的变形机理。结果表明,AZ31B镁合金在温度200℃以下时,不会发生动态再结晶,其机理主要为晶内变形。当变形温度达到200℃,在较高的应变速率时,原始晶粒仍然存在,且被拉长,此时的变形机理应为晶内变形;而在应变速率较低时,原始晶粒的晶界变为锯齿形,出现了极小的再结晶晶粒。当变形温度达到300℃时,在较高的应变速率下,发生了不充分的再结晶,部分原始晶粒仍然存在,且被拉长;而在应变速率较低时,再结晶充分进行,且晶粒有长大的趋势。在较低的应变速率时,随着温度的升高,断口由无韧窝或者韧窝浅而少的特征,逐渐发展为典型的延性韧窝聚合型断裂的特征,在高温时,甚至发展为沿晶断裂模式;在变形温度为200℃和300℃时,随着应变速率的增大,沿晶断裂形貌消失,韧窝聚合型延性断裂逐渐受到抑制,最后在较高的应变速率时,断口呈现出解理这一晶内断裂的典型特征。

关 键 词:镁合金  热拉伸  微观组织  断口形貌

Experimental research on microstructure of AZ31B magnesium alloy thin sheet under thermal tension
YANG Dong-feng,DONG Guo-jiang,ZHAO Chang-cai,HAO Hai-bin.Experimental research on microstructure of AZ31B magnesium alloy thin sheet under thermal tension[J].Journal of Plasticity Engineering,2011,18(2).
Authors:YANG Dong-feng  DONG Guo-jiang  ZHAO Chang-cai  HAO Hai-bin
Affiliation:YANG Dong-feng1 DONG Guo-jiang3(College of Vehicles and Energy,Yanshan University,Qinhuangdao 066004 China)ZHAO Chang-cai2 HAO Hai-bin4(College of Mechanical Engineering,Qinhuangdao 066004 China)
Abstract:The different features of microstructure and fracture morphology of AZ31B under different deformation conditions were researched adopting Gleeble-3500 thermal simulation machine,metallographic microscope and scanning electron microscope.The deformation mechanism was studied.The results show that dynamic recrystallization doesn't take place in AZ31B below 200℃,the main deformation mechanism is deformation within grain.At 200℃,when strain rate is rather fast,original grains still exist but are elongated,the deformation mechanism is still deformation within grain.When strain rate is slow enough,the shape of the borders of the original grain become saw-toothed,and a little recrystallized grains appeared.At 300℃ when strain rate is rather fast,inadequate recrystallization take place,some original grains still exist,and are elongated;When strain rate is slow enough,adequate recrystallization take place,and grains tended to become bigger.At rather slower strain rate,with temperature increasing,the fracture surface gradually turns to surface with typical ductile dimples accumulation from the surface composed of shallow and few dimples even without dimples.When temperature is high enough,intergranular fracture took place.At 200℃ or 300℃,with strain rate increasing,the morphology of intergranular fracture disappear with ductile dimples accumulation fracture being gradually inhibited;when strain rate is fast enough,cleavage appear on thefracture surface.
Keywords:magnesium alloy  thermal tension  microstructure  fracture morphology  
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