【作者】 王国伟；

【导师】 田修波；

【作者基本信息】 哈尔滨工业大学 ， 材料加工工程， 2009， 硕士

【摘要】 本文采用金属离子注入技术（MEVVA）在AISI201不锈钢表面制备铝层作为过渡层,在此基础上采用AlSi钎料对注铝后的不锈钢和工业纯铝（L2）进行了炉中钎焊。采用实验研究和理论相结合的方法,对钎焊连接工艺进行了优化,分别研究了工业纯铝与注铝不锈钢和不锈钢连接接头的界面结构及抗剪强度的变化。通过金相显微镜观察、X射线光电子能谱（XPS）、X射线衍射分析（XRD）、扫描电子显微镜（SEM）等检测手段对改性层界面形态和元素的浓度-深度分布、钎料的铺展和润湿、焊缝的形貌及成分分别进行了分析。确定了本实验中钢/铝钎焊的最佳工艺参数,研究了不同等离子注入处理参数对焊缝界面金属间化合物生长、钎缝微观形貌及接头力学性能的影响,阐明了温度、保温时间对焊缝组织形貌和界面生长行为的影响规律。注入改性后不锈钢表面钎料的润湿性得到明显改善,高的注入剂量和注入电压均可以显著提高钎料润湿性。当温度T=600℃、保温时间为t=5min时,Al/Al-Si/注铝不锈钢接头的界面结构为:Al/ Al-Si/Al₁₃Fe₄/FeAl₂/不锈钢。随着铝注入剂量和注入电压的增加,化合物层厚度越来越薄,剪切强度随之提高。而随着钎焊温度的升高和保温时间的延长,化合物层越来越厚,剪切强度随之降低。拉剪试验结果表明:当钎焊温度为600℃、保温时间为5min、注入电压V=40kV、注入剂量D=9×10¹⁷ions/cm²时,注铝不锈钢/Al接头的最高剪切强度为61MPa;相同参数下的未注铝不锈钢/Al接头的最高剪切强度为29Mpa。更多还原

【Abstract】 In this thesis, metal vapor vacuum arc （MEVVA） technique was utilized to implant aluminum into stainless steel substrate to fabricate a transition layer. AlSi solder was used to braze stainless steel and industrial pure aluminum （L2）. The brazing process has been optimized and the effect of aluminum implantation on interface structure and shear strgngth of the joint has also been focused onThe microstructure of the joints was analyzed by means of SEM, EPMA, XPS and XRD. Based on the interface structures identified in the joint, formation mechanism and process of interface structure were discussed.The changes of microstrure formed at different parameters were also analyzed.The wettability of solder has been markedly improved on the stainless steel implanted with aluminum, and high implantation dose and implantation voltage can both enhance significantly the solder wettability. By means of analyzing the interface reaction of alumina/Al-Si/implanted stainless steel joints, the optimal interface structure was determined to be Al（zoneⅠ）, Al-Si（zoneⅡ）, Al13Fe4, FeAl2（zoneⅢ）, stainless steel （zoneⅣ） when the brazing temperature was 600℃and holding time was 5min. With increasing implantation dose and implantation voltage, the intermetallic compound layer became thin. However, with increasing the brazing temperature and prolonging holding time, the intermetallic compound layer became thick.The shear strength was measured to evaluate the mechanical poperties of the joints. The results showed that the shear strengths of the joints increased with implantation dose increasing, implantation voltage increasing, proper brazing time or holding time. When implantation dose was 9×10¹⁷ions/cm², implantation voltage was 40kV, the brazing temperature was 600℃and holding time was 5 min, the maximum shear strengths of the aluminum/Al-Si/aluminum-implanted steel joint could reach 61MPa in contrast the shear strength of brazed joint without implantion was only 29.1MPa.更多还原