蓝宝石与TC4合金钎焊工艺及机理研究

发布时间：2018-07-17 02:29

【摘要】：蓝宝石和TC4的连接本质上属于陶瓷与金属的连接。而接头较大的残余应力是目前急需解决的问题。钎焊是连接陶瓷与金属最主要的研究方法,因此本课题采用钎焊对蓝宝石和TC4合金进行连接。把原位自生反应和增强相强化的思想以及中间层的方法应用到本课题中。对Ag-28Cu+x Ti体系Ag基钎料钎焊蓝宝石的可行性进行了研究,研究了Ag基钎料在蓝宝石抛光001晶面上的润湿性能,在Ti含量达到9wt.%时获得了理想的润湿角。使用Ag-28Cu+9wt.%Ti钎料实现了蓝宝石的钎焊连接并确定了典型钎焊接头的界面组织及相组成。进而探究了Ag-28Cu+x Ti体系钎料与蓝宝石结合的热力学条件和连接过程中界面组织的形成过程。为了缓解蓝宝石/TC4钎焊过程中较大的残余应力,采用原位自生Ti B晶须强化的方法对蓝宝石和TC4合金进行钎焊。对典型接头的界面组织进行了分析,接头组织为蓝宝石/Ti3(Cu,Al)3O/Ti2(Cu,Al)+Ti2Cu/Ti B+Ti B2+Ag(s.s)+Ti2Cu+Ti(Cu,Al)/(αTi+Ti2Cu)+Ti3Al+Ti2Cu/TC4合金。并阐述了温度以及复合钎料中Ti B2含量对接头组织及力学性能的影响。结合EDS能谱和热力学分析,解释了接头组织的形成机制。整个过程如下:钎料与母材间的固态接触阶段;界面Ti3(Cu,Al)3O反应层及Ti B晶须的形成阶段;Ti B晶须继续生成,界面反应层的生长及Ti2Cu、Ti2(Cu,Al)的形成阶段;Ti(Cu,Al)、Ti Cu的形成及(αTi)+Ti2Cu组织及Ag(s.s)相的析出阶段。采用原位自生Ti B晶须强化的方法对蓝宝石和TC4合金进行钎焊时,接头的强度并没有得到明显的强化,并且接头母材产生了裂纹。因此选择中间层方法来缓解接头的残余应力。通过采用Mo中间层和Ag-28Cu+9wt.%Ti+Mo粉复合钎料两种方法对蓝宝石和TC4合金进行钎焊,对接头的组织进行观察分析,并对各参数下的试件进行强度测试。通过金相和剪切强度测试结果对蓝宝石开裂的原因进行了分析。通过研究Mo中间层厚度对接头组织和性能的影响,发现随着接头中Mo中间层厚度的增加,裂纹尺寸减小并消失。Mo中间层厚度达到300μm时,强度达到最大值,13.25MPa。
[Abstract]:The connection between sapphire and TC4 is essentially a connection between ceramic and metal. However, the large residual stress of the joint is an urgent problem to be solved at present. Brazing is the most important research method to connect ceramics with metals, so brazing is used to connect sapphire and TC4 alloys. The idea of in situ autogenous reaction and enhancement phase strengthening and the method of interlayer are applied to this subject. The feasibility of Ag base brazing sapphire with Ag-28Cu x Ti system was studied. The wettability of Ag-base brazing filler metal on the polished 001 crystal plane of sapphire was studied. The ideal wetting angle was obtained when Ti content reached 9wt.%. Using Ag-28Cu 9wt.Ti filler metal, the brazing joint of sapphire was realized and the interface structure and phase composition of typical brazing joint were determined. Furthermore, the thermodynamic conditions for the bonding of Ag-28Cu x Ti solder with sapphire and the formation of interfacial structure in the bonding process were investigated. In order to alleviate the large residual stress during sapphire / TC4 brazing, in situ Ti B whisker strengthening method was used to braze sapphire and TC4 alloys. The interfacial microstructure of typical joints was analyzed. The microstructure of the joints is sapphire / Ti3 (Cunal) 3O / Ti2 (Cunal) Ti2Cu/ TiB2 Ag (s.s) Ti2CuTi (Cunal) / (伪 TiTi2Cu) Ti3AlTi2Cu- / TC4 alloy. The effects of temperature and TiB2 content on the microstructure and mechanical properties of the joint were discussed. The formation mechanism of joint microstructure was explained by EDS energy spectrum and thermodynamic analysis. The whole process is as follows: the solid contact stage between the filler metal and the base metal, the Ti _ 3 (Cu-Al) _ 3O reaction layer at the interface and the formation stage of the Ti _ B whisker. The growth of the interface reaction layer and the formation of Ti _ 2Cu _ 2O _ 2 (Cu-Al) and the precipitation of (伪 Ti) Ti _ 2Cu structure and Ag (s.s) phase. In situ brazing of sapphire and TC4 alloys by in-situ Ti B whisker strengthening, the strength of the joint was not obviously strengthened, and the crack occurred in the base metal of the joint. Therefore, the interlayer method is chosen to alleviate the residual stress of the joint. The sapphire and TC4 alloys were brazed by Mo interlayer and Ag-28Cu 9wt.Ti Mo composite solder. The microstructure of the joints was observed and analyzed, and the strength of the specimens under various parameters was tested. The causes of sapphire cracking were analyzed by metallography and shear strength test. By studying the effect of Mo interlayer thickness on the microstructure and properties of the joint, it is found that with the increase of Mo interlayer thickness in the joint, the crack size decreases and disappears. When the thickness of Mo interlayer reaches 300 渭 m, the strength reaches the maximum value of 13.25 MPA.
【学位授予单位】：哈尔滨工业大学
【学位级别】：硕士
【学位授予年份】：2017
【分类号】：TG454

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