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通过光学显微镜(OM)、扫描电子显微镜(SEM)、X射线衍射仪(XRD)分析手段对加速腐蚀环境下的Zn-2Al钎料的组织和性能进行研究。结果表明:随着腐蚀时间的延长,钎料中O,H含量不断增加;Zn-2Al钎料抗拉强度和延伸率随着腐蚀时间的延长逐渐降低;腐蚀深度与腐蚀时间呈线性关系:D=A+Bt,其中A=-30.50083,B=34.81966,Zn-2Al钎料的腐蚀没有自抑制倾向;水汽腐蚀主要发生在晶界处,当腐蚀达到一定程度后,形成了大量的腐蚀裂纹和腐蚀孔洞;应力的存在加剧了Zn-Al钎料在湿热环境中的晶间腐蚀,易在晶界处形成腐蚀裂纹,腐蚀环境对裂纹的扩展有明显的加速作用,裂纹沿着晶界处不断扩展;晶间腐蚀过程是晶内富锌β相作为阴极,晶界处富铝α相作为阳极而溶解的电化学腐蚀过程;XRD分析结果显示腐蚀产物主要有Al2O3,Zn O,Al(OH)3,Zn(OH)2,与前面所测腐蚀后钎料中氧氢含量增加相一致,钎料在湿热环境中进行着电化学腐蚀并伴随着氧化。
The microstructure and properties of Zn-2Al brazing alloy under accelerated corrosion were investigated by optical microscope (OM), scanning electron microscopy (SEM) and X-ray diffraction (XRD) The results show that the content of O and H in the brazing filler metal increases with the increase of the corrosion time. The tensile strength and elongation of the brazing filler metal Zn-2Al gradually decrease with the increase of the corrosion time. The corrosion depth is linear with the corrosion time: D = A + Bt, where A = -30.50083 and B = 34.81966, corrosion of Zn-2Al solder does not tend to self-inhibit; water vapor corrosion occurs mainly at the grain boundaries, and when corrosion reaches a certain degree, a large amount of corrosion cracks and The existence of stress aggravates the intergranular corrosion of Zn-Al solder in wet and hot environment, easily forms the corrosion crack in the grain boundary, the corrosion environment accelerates the crack growth obviously, and the crack keeps along the grain boundary The results show that the main corrosion products are Al 2 O 3, Zn O, Al (OH) 2, Al 2 O 3, Al 2 O 3, 3, Zn (OH) 2, consistent with the increased oxygen and hydrogen content of the brazing material tested before, and the brazing material is subjected to electrochemical corrosion in the hot and humid environment accompanied by oxidation.