【作者】 范奇；

【导师】 张华；

【作者基本信息】 北京交通大学 ， 工程热物理， 2009， 硕士

【摘要】 Ti₃AlC₂陶瓷是近年来发展起来的一种新型陶瓷材料,因其兼具陶瓷和金属的优异性能,在机械、能源、航空、电子和化工等领域具有广泛的应用前景。本文首次采用无焊料电弧焊接的方法进行了Ti₃AlC₂陶瓷材料与Cu（Mg）合金的焊接研究,证实了焊接方法的可行性,揭示了接头的组织结构和性能与焊接工艺之间的关系,探讨了电弧加热过程中焊接工艺参数对焊接母材内温度场的影响规律,这些研究工作及成果将为大尺寸、复杂形状及多属性Ti₃AlC₂陶瓷材料构件的低成本制造奠定基础,促进Ti₃AlC₂陶瓷材料的工程应用。本文采取试验与数值模拟相结合的方法进行研究。采用无焊料电弧焊接方法对Ti₃AlC₂陶瓷和Cu（Mg）合金进行焊接试验,利用扫描电子显微镜（SEM）和能谱分析仪（EDS）观察接头界面的显微结构和元素分布,采用X射线衍（XRD）分析焊接接头的物相组成,通过四点弯曲实验测试焊接试样的强度,并测定焊接接头的电阻率。针对焊接中的电弧加热过程,基于有限元分析建立了二维轴对称简化模型,通过ANSYS数值模拟研究焊接电流、电弧持续时间、试样的尺寸等焊接条件对焊接母材内温度场的影响规律,确定最佳工艺参数。研究表明,电弧焊接法可以实现Ti₃AlC₂陶瓷和Cu（Mg）合金的牢固连接,焊接接头的强度超过了Ti₃AlC₂陶瓷材料本身的强度,其焊接机理在于两焊接端面之间的界面反应。电弧加热过程的工艺参数及试样尺寸决定了焊接端面的温度分布,进而决定了Cu（Mg）合金的熔化情况及Ti₃AlC₂陶瓷的组织变化,是影响接头结构和性能的关键因素。在电弧电流密度为4.7A/mm²～5.7A/mm²时,拉弧时间为1s～1.5s时,Cu（Mg）合金的熔化量和Ti₃AlC₂陶瓷焊接端温度为最佳,形成TIC_x相和Cu（Al,Mg）相复合的接头结构,且TiC_x颗粒细小、均匀弥散分布,接头具有较高的强度和良好的导电性能。更多还原

【Abstract】 Ti₃AlC₂ ceramic,as a newly developed ceramic material with both ceramic and metal traits,is to be widely applied in areas such as mechanism,energy,avigation, electronics and chemical industry.For the first time the welding of Ti₃AlC₂ ceramic and Cu（Mg） is studied in this paper by the method of arc welding without solder,which has confirmed the feasibility of the welding method,opened out the relationship between the organization and performance of the joints and the welding technics,and probed into the influence of the welding technics parameter in arc heating process on the temperature field inside the welding material.The study and its result will lay a foundation for the low-cost manufacture of the big-sized,complicatedly shaped and multiattribute Ti₃AlC₂ ceramic component,which can advance the application of Ti₃AlC₂ ceramic material in industry.A method which combines experiment and numerical simulation is adopted.A welding experiment on Ti₃AlC₂ ceramic and Cu（Mg） was done with the method of arc welding without solder.By using SEM and EDS the microstructure and the element distribution on the joints interface were observed.Besides by using XRD the substance composition of the joints was analyzed.The bending intensity on the welding sample were measured and the intensity and resistance rate of the joints were tested.As to the arc heating process of the welding,a simplified model of the two-dimensional symmetry was built up.By the ANSYS numerical simulation the influence of the welding qualifications such as the arc current,the arc time,the sample size on the temperature field inside the welding material was studied and the best technics parameter was fixed.The study indicates that arc welding can help combine firmly the Ti₃AlC₂ ceramic and Cu（Mg） and the intensity of welding joints exceeds the one of the Ti₃AlC₂ ceramic material itself.Reaction between two welding interface determine it’s welding mechanism,temperature distribution of welding face of arc heating process and the melting of Cu（Mg） alloy and the organization of Ti₃AlC₂ Ceramic are decided by technics parameter and the sample size which are the key factors influenced the structure and properties of joints.When the arc current density is between 4.7A/mm² and 5.7A/mm² and the arc time is between 1s and 1.5s,the melting quantum of Cu（Mg） and the temperature on the welding point of the Ti₃AlC₂ ceramic are the best.Besides the Cu（Mg） and the Ti₃AlC₂ ceramic react and make the joints structure of TiC_x and Cu（Al,Mg）,with the TiC_x tiny and dispersed equably,and with the joints having high intensity and good electric characteristics.更多还原