挤压态WE43镁合金夹杂致裂的研究  

Study on inclusion cracking for extruded WE43 magnesium alloy

作　　者：吕刚 何建丽[1] 赵卫东 何进 Lyu Gang;He Jianli;Zhao Weidong;He Jin(School of Materials Engineering,Shanghai University of Engineering Science,Shanghai 201620,China)

机构地区：[1]上海工程技术大学材料工程学院,上海201620

出　　处：《锻压技术》2022年第2期192-198,共7页Forging & Stamping Technology

基　　金：国家自然科学基金资助项目(51805313)。

摘　　要：为了研究挤压态WE43镁合金夹杂物致裂的原因及机理,利用CT扫描仪扫描了WE43镁合金试样,观察挤压态WE43镁合金中夹杂物的形貌及尺寸分布,利用Gleeble-3800热模拟试验机在不同变形温度(150和250℃)、不同应变速率(0.001、0.01、0.1和1 s^(-1))条件下对镁合金试样进行了压缩试验至其断裂。通过光学显微镜和扫描电子显微镜对断裂试样裂纹附近区域形貌进行观察及分析。结果表明:挤压态WE43镁合金中的夹杂物主要为球形(或近球形),夹杂物尺寸在5~10μm范围内的占比约为42.94%。WE43镁合金的临界断裂应变约为0.3,且在试验温度下WE43镁合金的真应力与应变速率之间不敏感。在裂纹边缘及裂纹扩展方向上发现的夹杂物是镁合金致裂的重要原因。EDS结果表明:变形温度为150℃时,致裂的水滴状夹杂物成分为Mg_(12)Nd;而变形温度为250℃时,致裂的块状夹杂物成分为Mg_(24)Y_(5)。To study the reason and mechanism of inclusion cracking for extruded WE43 magnesium alloy, the WE43 magnesium alloy sample was scanned by scanner nano-CT to observe the morphology and size distribution of inclusions in the extruded WE43 magnesium alloy, and the WE43 magnesium alloy sample is subjected to compression tests until fracture by thermal mechanical stimulator Gleeble-3800 at different deformation temperatures(150 and 250 ℃) and different strain rates(0.001,0.01, 0.1 and 1 s^(-1)). Then, the morphologies near the crack region of fracture samples were observed and analysed by optical microscope and scanning electron microscope.The results show that the inclusions in the extruded WE43 magnesium alloy are mainly spherical(or nearly spherical), and the size of the inclusions is about 42.94% in the range of 5-10 μm. The critical fracture strain of WE43 magnesium alloy is about 0.3, and there is no sensitivity between true stress and strain rate of WE43 magnesium alloy at the test temperature. The inclusions found at the crack edge and the crack propagation direction are important causes of magnesium alloy cracking. The EDS results show that when the deformation temperature is 150 ℃, the composition of fracturing water droplet-shaped inclusion is Mg_(12)Nd, while when the deformation temperature is 250 ℃,the composition of fracturing massive inclusion is Mg_(24)Y_(5).

关 键 词：WE43镁合金 夹杂物 裂纹 临界断裂应变 变形温度 

分 类 号：TG146.2[一般工业技术—材料科学与工程]