Y_2O_3和Al-Si-Mg系矿化剂复合改性陶瓷型壳的高温抗变形性研究

High Temperature Anti-deformability of Composite Modified Ceramic Shell with Y_2O_3 and Al-Si-Mg Series Mineralizer

为了改善单晶叶片用陶瓷型壳的高温抗变形性能,利用Y_2O_3和Al-Si-Mg系矿化剂复合制备添加量为2%(质量分数,下同),4%和6%的型壳试样,对试样的热膨胀性和高温自重变形性进行研究。结果表明:随着添加量的增加,型壳的高温热膨胀性和高温自重变形率先减小后增大,当添加量为4%时,改善效果最佳,线膨胀率和自重变形率在1500℃的最小值为0.66%和0.55%,且复合矿化剂对高温自重变形的平均降低效率是热膨胀性的2倍。复合矿化剂改性型壳的机理主要以桥连状莫来石为微结构骨架及填充晶体间的细小球状钇铝石榴石(YAG)来阻碍玻璃相的黏性流动,共同提高型壳抗变形性。但添加量过多,则会产生大量玻璃相,削弱型壳的高温性能。

In order to improve the high temperature anti-deformability of ceramic shells for single crystal blade,composite modified ceramic shell specimens of Y2O3 and Al-Si-Mg series mineralizer were prepared with addition of 2%（mass fraction,the same below）,4%and 6%,then the thermal expansion and high-temperature self-loaded deformation of specimens were studied.The results show that high temperature thermal expansion and self-loaded deformation firstly reduced and then increased with the increase of the addition,when content is 4%,the test improvement is obtained,the minimum values of the linear expansion and high-temperature self-loaded deformation are 0.66% and0.55%at 1500℃,and the average decrease efficiency of the composite mineralizer on high-temperature self-loaded deformation is twice that of thermal expansion.The mechanism of composite mineralizer to modify the shell is to prevent the viscous flow of glass phase by bridging mullite as micro framework and fine globular yttrium aluminum garnet（YAG）inserted between crystals,to jointly improve anti-deformation ability of the shell.However,adding too much,it will produce a large number of glass phase,weakening high temperature performance of the shell.