Microstructure and hot corrosion resistance of Si-Al-Y coated TiAl alloy

In order to obtain a high-performance surface on TiAl alloy that can meet the requirements in hot corrosion environment,Si-Al-Y coatings were fabricated by pack cementation process at 1050℃for 4 h.Corrosion behaviors of the TiAl alloy with and without Si-Al-Y coatings are compared to illustrate the factors and corresponding mechanism in molten salt environment of 25 wt%K2SO4 and 75 wt%Na2SO4 at 900°C.The obtained Si-Al-Y coating was mainly composed of a TiSi2 outer layer,a(Ti,X)5Si4 and(Ti,X)5Si3(X represents Nb or Cr element)middle layer,a TiAl2 inner layer and a Al-rich inter-diffusion zone.The inter-phase selective corrosion containing corrosion pits extending alongα2 phase from lamellar interfaces in hot corrosion tested TiAl alloy was observed.However,by being coated with Si-Al-Y coating,the hot corrosion performance of TiAl alloy was improved remarkably.

阴极靶材外套的研究与制备

试验研究了阴极靶材外套的铸造工艺及性能,进行了X光检测、机械加工检测、化学成分分析、电镜分析。结果表明:国产铝钇合金外套铸件质量优异,合金成分均匀,内部组织与进口原件相同,可以替代进口产品。