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采用非自耗电弧熔炼法,制备Ti-44Al-4Nb-2Cr-(W,B)(at.%)合金。通过X射线衍射、金相观察、扫描电镜及透射电镜,研究Ti-44Al-Nb-Cr-(W,B)合金的显微组织与凝固特征。结果表明,铸造合金的晶粒细小,平均晶粒度为40#m,铸态组织中$相与%相存在“伴生”现象。同时,合金中一定量&相稳定元素W和Nb的加入,使高温’相得以在凝固过程中保留到室温,这种少量(相的存在也限制了)相晶粒的长大。
Ti-44Al-4Nb-2Cr- (W, B) (at.%) Alloy was prepared by non-consumable arc melting method. The microstructure and solidification characteristics of Ti-44Al-Nb-Cr- (W, B) alloy were investigated by X-ray diffraction, metallography, scanning electron microscopy and transmission electron microscopy. The results show that the grain size of the cast alloy is very small and the average grain size is 40 # m. The phase and the% phase in the as-cast microstructure have “associated ” phenomenon. At the same time, the addition of a certain amount of phase stabilizing elements W and Nb in the alloy allows the high temperature phase to be retained to room temperature during the solidification process. This small amount (phase presence also limits the growth of phase grains).