真空自耗电弧熔炼制备大尺寸TiAl基合金铸锭

TiAl Ingot with Large Scale Prepared by VAR Process

通过选择合适中间合金,并控制最佳熔炼工艺,以真空自耗电弧两次熔炼制备了名义成分为Ti-32.3Al-4.7Nb-2.6Cr-0.9(W,Mo)(质量分数)的TiAl合金铸锭。该TiAl合金铸锭尺寸为160 mm×380 mm,其组分中高熔点元素Nb,W,Mo等在铸锭横截面的径向上分布均匀,O,N,H等气体间隙元素含量较低,Al元素在铸锭纵截面中心轴线上的质量分数与目标成分偏差为±0.8%,显示出优良的冶金质量。金相分析结果显示,该TiAl合金铸锭的组织为近片层组织,铸锭边缘晶粒尺寸要显著小于其中间及心部的晶粒尺寸。

Using optimized master alloys and controlling the smelting process,the Ti-32.3Al-4.7Nb-2.6Cr-0.9（W,Mo）（mass fraction）alloy ingot with the dimension of 160 mm×380 mm was prepared by means of Vacuum Arc Remelting（VAR）process.The ingot exhibits homogeneous element distribution,especially the niobium,tungsten and molybdenum refractory metal element,in its transverse section and low impurity levels of undesired interstitial elements,such as oxygen,nitrogen and hydrogen.Aluminum content deviation along the middle axis of ingot longitudinal section is about ±0.8 %.The microstructure of the TiAl ingot is near lamellar;the grain size of edge region is much smaller than that of R/2 and center region.