C对一种镍基高温合金与陶瓷型壳界面反应及润湿性的影响

EFFECT OF C ON THE INTERFACIAL REACTION AND WETTABILITY BETWEEN A Ni-BASED SUPERALLOY AND CERAMIC MOULD

采用座滴法研究了C对一种高温合金与陶瓷型壳的界面反应及润湿性的影响.通过SEM和EPMA研究了合金与陶瓷型壳的界面组织形貌及反应区元素分布.利用Thermo-Calc软件计算了合金熔体中C,Cr和Al的活度,分析了C含量对合金熔体中C,Cr和Al的活度的影响.探讨了合金/陶瓷界面反应与润湿性的关系.结果表明,合金中C含量高于0.1%时,C的活度明显增大,合金熔体与陶瓷型壳发生界面反应,合金熔体/陶瓷体系由非反应润湿变为反应润湿,合金表面产生黏砂层且合金中Cr和Al扩散到陶瓷表面.

Superalloy components are always produced by the way of investment casing. During investment casting, interfacial reactions may take place and bring about metal contamination and defect formation on the surface of the components. The influence of C content on the interfacial reaction and wettability between a Ni-based superalloy and ceramic mould was investigated by using a sessile drop method. The interfacial morphology and elements distribution were studied by SEM and EPMA. Activities of C, Cr and Al were calculated by using ThermoCalc software. The relationship between interfacial reaction and wettability was discussed. It was found that when C content was higher than 0.1%, activity of C increased greatly and interfacial reaction took place. The wettability varied from non-reactive wetting to reactive wetting. In the reactive wetting systems, sand adhesions appeared and Al and Cr diffused to the ceramic surface.