摘要
采用显微组织观察的方法研究了Ti-Al-Nb-W-B合金在1265℃,18 h热处理过程中的组织演变规律.对合金的铸态、均匀化处理态合金及1265℃,18 h热处理态微观组织进行了观察,研究了钨含量与Ti-Al-Nb-W-B合金热处理微观组织演变的关系.结果表明:热处理态组织的层片特征弱化,γ片增厚,而体积分数减少,α2片则增厚更多,且体积分数增多.当合金中钨含量不同,其组织中的晶团尺寸出现差异,随着钨含量的增加,晶团尺寸减小,但减小的程度较小;白色点状的β(B2)相析出,呈弥散分布;随着钨含量的增加,β(B2)析出相的数量有增加的趋势,且更多地分布在晶界,尤其在晶界的交角处,析出相可有效钉扎晶团长大:在1265℃保温时,非连续长大非常缓慢.
The microstructures of as-cast Ti - Al - Nb - W - B alloy after annealed and heat treated at 1265 ℃ for 18 h were observed. The microstructures at different states were compared. The relation of content of tungsten with evolution of microstructure of heat treated TiAl was analyzed. The results showed that the lamellar characteristic after heat treated alloy was weakened with coarsening of α2 plates, increasing of their volume fraction, and with coarsening of γ plates and decreasing of their volume fraction. With increasing content of tungsten, the colony size of alloy decreased and slowly. The second white phases distributed dispersively in colonies and the β （B2） phases precipitate at the grain boundaries especially in the corner of the grain boundaries with increasing content of tungsten, which could pin the of grains. While the Ti - Al - Nb - W - B alloy was held at 1265 ℃, the discontinuous coarsening was very slow.
出处
《材料科学与工艺》
EI
CAS
CSCD
北大核心
2007年第1期1-5,共5页
Materials Science and Technology
