【作者】 刘伟娜；

【导师】 何景山；

【作者基本信息】 哈尔滨工业大学 ， 材料加工工程， 2007， 硕士

【摘要】 本文针对镍基高温合金жс6у-ви叶片铸造缺陷的修补需要,进行了жс6у-ви合金电子束钎焊修复工艺基础研究,并对两种不同开槽形式电子束钎焊过程中的温度场及应力场进行了有限元数值分析。对Впр27和Впр24两种粉末钎料在жс6у-ви合金上进行了钎料的铺展性试验。根据铺展性试验结果,最终选择了Впр24钎料对жс6у-ви合金进行钎焊连接。利用扫描电镜、电子探针和X-射线衍射等分析手段,分析了接头的界面组织结构,确定了界面反应产物,探讨了工艺参数对接头界面组织和力学性能的影响。试验结果表明:工艺参数束流对钎料的润湿铺展性影响最大,同时对接头界面组织形态及其力学性能影响显著。采用Впр24钎料的电子束钎焊接头界面反应产物主要有α(Co,Ni)+(Ni)和Ni-Cr-Co-Mo固溶体及NiW,Ni3(Al,Ti),Ni3Nb金属间化合物。当聚焦电流、加热时间一定时,随着束流的增加,钎焊接头界面产物的种类并未发生改变,但界面各反应层的厚度发生一定的变化。通过工艺试验,确定采用Bпp24钎料对жс6у-ви合金进行电子束钎焊连接的相对最优工艺参数为:束流2.4~2.7mA,加热时间400~560s,聚焦电流1790~2200mA,此时接头抗拉强度可达340~400MPa。利用有限元软件MSC.Marc建立了两种不同开槽形式电子束钎焊过程中的温度场有限元数学模型,并在温度场计算基础上采用热力间接耦合方法对应力场进行了数值分析。计算结果表明:距离钎焊界面0.4~1.5mm的范围是应力集中区域;开非贯通槽时的残余应力比开贯通槽时的大;试板上沿y方向的应力大于x方向上的应力。更多还原

【Abstract】 In order to meet the repair requirement of engine vanes of Ni-based high temperature alloyжс6у-виwith casting defects, the basic repairing technology on electron beam brazing ofжс6у-виalloy was studied in this paper. Meanwhile, the temperature field and the stress field of two different grooving forms during the process of electron beam brazing were analyzed by the finite element numerical simulation.The spreading experiments ofВпр27 andВпр24 powder brazing metals onжс6у-виalloy were carried out before electron beam brazing. According to the results of spreading experiment,Впр24 was preferably selected to brazeжс6у-виalloy. The interfacial structures and the reaction products of the brazing joints were analyzed by SEM, EPMA and XRD, and the effect of the technological parameters were discussed on the interfacial structures and mechanical properties. Experimental results showed that beam current is the most important parameter for the spreadability of brazing metals, meanwhile to the interfacial structures and mechanical properties of the joints. The interfacial structures of the electron beam brazing joints by usingВпр24 mainly containedα(Co,Ni)+(Ni) and Ni-Cr-Co-Mo solid solutions, NiW,Ni3(Al,Ti), and Ni3Nb intermetallic compounds. When focus current and heating time were fixed with the increment of beam current, the kinds of the interfacial structures of the brazing joints did not change, while the thickness of the reaction layers changed. Through technological experiments, the relative best technological parameters were gained as beam current 2.4~2.7mA, heating time 400~560s, focus current1790~2200mA, and the strengths of the joint achieved 340~400MPa.The FEM software MSC.Marc was employed to calculate the temperature field of the EBB samples with two different grooving forms. Based on the calculation results of the temperature fields, the stress field was simulated by heat-force indirect coupling. The simulated results of the stress field using different grooving forms indicated that the range of 0.4~1.5mm from the brazing interface was the stress concentration region; the residual stress of the sample with no-through slot was bigger than that with through slot; the stress along y direction was larger than that along x direction.更多还原