【摘要】 以TiH2粉、FeV80合金粉、Al粉和Fe粉为原料,采用放电等离子烧结法(烧结温度为800～1 200℃,保温时间为10min),制备Ti-1Al-8V-5Fe(Ti185)合金,通过烧结致密化曲线和采用成熟的蠕变模型准确评估有效应力指数(n)和致密激活能(Qd),研究致密化机理。结果表明,在较低温度下(800～1 000℃)烧结时,合金快速致密,无明显晶粒长大;当烧结温度达到1 100℃后,合金缓慢致密,晶粒明显长大。在800～1 000℃烧结时,保温前期为致密阶段,具有低的有效应力指数n和表观激活能Qd(n=1,Qd=52 kJ/mol),为低有效应力阶段,晶界扩散控制致密化过程;保温后期为较高的有效应力阶段,n=3,Qd=175.7 kJ/mol,材料的致密化机制由位错攀移所控制。更多还原

【Abstract】 TiH2, FeV80, Al and Fe powders were used as raw materials, and the spark plasma sintering was used to prepare Ti-1 Al-8 V-5 Fe(Ti185) alloys at 800-1 200 ℃ for 10 min. The effective stress exponent(n) and the densification activation energy(Qd) were evaluated by the sintering densification curve and mature creep model, which were used to study the densification kinetics of Ti185 alloys. The results showed that the alloys were rapidly densified without obvious grain growth at low temperature(800-1 000 ℃). When sintering temperature reached 1 100 ℃, the alloys were slowly densified with obvious grain growth. During sintering at 800-1 000 ℃, the densification stage in the early stage of dwelling had low effective stress exponent n and apparent activation energy Qd(n=1, Qd=52 kJ/mol), which was the stage of low effective stress, and grain boundary diffusion controlled the densification process of alloys. However, the later stage of dwelling corresponded to a higher effective stress stage, with n=3 and Qd=175.7 kJ/mol. The densification mechanism of the alloys was controlled by dislocation climbing.更多还原