原位生成Al3Zr/Al基复合材料等离子焊接组织及表面腐蚀行为

Microstructure and Surface Corrosion Behavior of Plasma Welding Area of Al3Zr/Al Matrix In-situ Composites

以5%Al3Zr/铝基复合材料(质量分数)为研究对象,以Ar气体为离子气体,Al-Ti-B为丝材进行等离子焊接。用电化学综合测试仪测定了焊接区在3.5%Na Cl溶液中的腐蚀极化曲线。采用扫描电子显微镜(SEM)、X射线衍射仪(XRD)对复合材料及其焊缝的组织和相组成进行了分析和表征,研究了Al3Zr/Al基复合材料等离子焊接后在3.5%Na Cl溶液中的腐蚀行为和腐蚀机理。SEM分析结果表明,等离子弧焊接可获得较好的焊缝组织,焊缝组织主要由Al3Ti相和Al基体组成,Al3Ti相呈条状和球形。电化学极化曲线表明,材料在熔核处的耐蚀性略低于母材,焊缝处浸泡腐蚀机理为Al3Ti相和基体相的电极电位不同形成原电池反应。

5 wt%Al3Zr/aluminum matrix composites were taken as the research object,and plasma welding was conducted with Ar gas as ion gas and Al-Ti-B as wire materials.The corrosion polarization curve of weld area in 3.5%Na Cl solution was measured by electrochemical comprehensive tester.Scanning electron microscope(SEM)and X-ray diffraction analyzer(XRD)were used to analyze and characterize the microstructure and phase composition of the composite and its weld.The corrosion behavior and corrosion mechanism of Al3Zr/aluminum matrix composites after plasma welding were studied in 3.5%Na Cl solution.The SEM analysis results show that through plasma arc welding,a better weld can be obtained.The weld microstructure is mainly composed of Al3Ti phase and Al matrix,and the Al3Ti phase is striped and spherical.The electrochemical polarization curves indicate that the corrosion resistance of the materials at the nugget is slightly lower than that of the base metal.The immersion corrosion mechanism of weld is that the Al3Ti phase and the matrix phase behave as the anode and cathode of a primary cell.