| 摘要: |
| 采用TIG焊对5 mm厚的AZ91镁合金板材进行焊接,利用X射线衍射(XRD)、光学显微镜(OM)、扫描电镜(SEM)及拉伸试验机等试验设备进行检测、试验,研究不同焊接电流对接头显微组织与性能的影响规律.结果表明,焊缝区由基体α-Mg和附集于晶界的β-Al12Mg17两相组成;随着焊接电流的增加,焊缝晶粒组织逐渐粗化,同时易产生裂纹等缺陷,使接头力学性能降低.当焊接电流为100 A时,接头的抗拉强度达到最佳,其抗拉强度为252 MPa,断后伸长率6.9%. |
| 关键词: 焊接电流 镁合金 TIG焊 组织与性能 |
| DOI： |
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| 基金项目:辽宁省自然科学基金资助项目(20072041);辽宁省教育厅资助项目(062478) |
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| Research of microstructure and mechanical behavior of welded joint of AZ91 magnesium alloy |
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LIU Zhengjun, ZHAO Fudong, SU Yunhai, QI Yiuhong
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Material Science and Engineering, Shenyang University of Technology, Shenyang 110000, China
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| Abstract: |
| The AC TIG was applied on AZ91 magnesium alloy plate(in 5mm thickness).The effect of different welding currents on microstructure and properties of surfacing layer was investigated by X-ray diffraction(XRD),Optical Microscope(OM),Scanning Electron Microscope(SEM),and Tensile Tester.The results show that with the increasing of welding current,the form of welding seam become bad and the grain growth get coarse.At the same time,gas porosity and crack are easy to by produced,which reduce the properties of the joint.The microstructure of the weld zone is composed of α-Mg matrix and β-Al12Mg17 phase.When the welding current is 100A,the mechanical properties of welded joints reach maximum,at this point tensile strength is 252 MPa,percentage elongation is 6.9%. |
| Key words: welding current magnesium alloy TIG structure property |
