室温一道次等通道转角挤压后纯镁的组织和性能

发布时间：2018-03-09 16:51

本文选题：纯镁　切入点：等通道挤压　出处：《哈尔滨工程大学学报》2017年02期 　论文类型：期刊论文

【摘要】：由于镁为密排六方结构,室温塑性较差,目前纯镁的等通道挤压(equal channel angular pressing,ECAP)研究一般是在高温下进行的。为了实现纯镁在室温下的ECAP大变形,本次实验中采用创新性方法,将方铁套包套的工业纯镁圆棒在通道横截面尺寸为12 mm×12 mm的模具中进行室温等通道转角挤压,借助于纯铁优良的加工塑性以及在挤压过程中对纯镁产生的较强束缚力,成功制备了表面光滑且无明显裂纹的纯镁挤压试样,使用光学显微镜(OM),微机控制电子万能试验机研究了一道次挤压后纯镁的组织和力学性能。最后,用扫描电子显微镜(SEM)对拉伸断口进行了观察。结果表明,一道次挤压后,纯镁的晶粒得到明显细化,晶粒尺寸由最初的几百微米下降到几个微米,屈服强度和拉伸强度分别达到97 MPa和118 MPa,比未挤压前明显提高。同时,由于在ECAP过程中试样发生了剧烈塑性形变,挤压前后断口形貌明显不同。
[Abstract]:The six party due to the close packed structure, poor plasticity at room temperature, the pure magnesium ECAP (equal channel angular pressing, ECAP) research is generally done at high temperature. In order to achieve the pure magnesium at room temperature ECAP large deformation, innovative methods in this experiment, the iron mold package the set of pure magnesium rod in the channel cross-section size of 12 mm * 12 mm in room temperature ECAP, with excellent plasticity and iron processing of pure magnesium in the extrusion process with strong binding force, successful preparation of pure magnesium surface is smooth and no obvious crack extrusion the sample, using optical microscopy (OM), a research machine passes and mechanical properties of pure magnesium electronic universal testing control microcomputer. Finally, using scanning electron microscopy (SEM) on the tensile fracture morphology was observed. The results showed that one passes, pure magnesium The grains are refined obviously, the grain size decreased from hundreds of microns to a few microns, the yield strength and tensile strength reached 97 MPa and 118 MPa respectively, significantly higher than not before extrusion. At the same time, because the sample in ECAP during severe plastic deformation before and after extrusion broken lip profile significantly different.

【作者单位】：太原理工大学材料科学与工程学院;
【基金】：国家自然科学基金项目(51474152)
【分类号】：TG379

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