通过预涂覆SiC优化AZ31B镁合金DE-GMAW焊缝的显微组织及提升力学性能

发布时间：2018-03-13 20:15

本文选题：SiC　切入点：AZB镁合金　出处：《材料导报》2017年20期 　论文类型：期刊论文

【摘要】：研究了碳化硅(SiC)颗粒涂覆量对2mm厚AZ31B镁合金双电极气体保护焊DE-GMAW焊缝的宏观形貌、显微组织和力学性能的影响。利用光学显微镜、扫描电镜和X射线衍射分析技术(XRD)对接头的显微组织、相及相的成分进行分析。同时采用维氏硬度试验计和万能试验机对焊接接头的显微硬度和抗拉强度分别进行测量。结果表明,随着SiC涂覆量的增加,焊接接头熔深和深宽比先增大后减小。XRD测试结果显示,SiC的添加并不改变焊缝中相的组成,焊缝由α-Mg和β-Mg_(17)Al_(12)组成。SiC可以细化α-Mg晶粒,打断焊缝中β-Mg_(17)Al_(12)相,起到弥散强化的效果。但SiC涂覆量达到一定值后,随着SiC涂覆量的继续增加,α-Mg晶粒粗化,β-Mg_(17)Al_(12)相的弥散强化作用不再增加。焊接接头的显微硬度和抗拉强度随着SiC涂覆量的增加先增大后减小。
[Abstract]:The effects of sic coating amount on the macroscopic morphology, microstructure and mechanical properties of DE-GMAW weld of 2mm thick AZ31B magnesium alloy welded by gas shielded double electrode were studied. Scanning Electron Microscopy (SEM) and X-ray diffraction Analysis (XRD) for the microstructure of the joints, The microhardness and tensile strength of welded joints were measured by Vickers hardness tester and universal tester respectively. The results showed that the microhardness and tensile strength of welded joints increased with the increase of SiC coating amount. The results of XRD test show that the addition of sic does not change the composition of the phase in the weld, and the weld is composed of 伪 -Mg and 尾 -Mg17AlStup (12). Sic can refine the 伪 -Mg grain and interrupt the 尾 -MgS17 / AlStud12) phase in the weld. But when the amount of SiC coating reaches a certain value, With the further increase of SiC coating amount, 伪 -Mg grain coarsening, the dispersion strengthening effect of 尾 -MgMg-17AlC12) phase is no longer increased. The microhardness and tensile strength of welded joints increase first and then decrease with the increase of SiC coating amount.
【作者单位】：南昌大学机电工程学院;
【基金】：国家自然科学基金(61165008;51665037)
【分类号】：TG457.19

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