CAJ | 학술논문

将快速凝固Ti-46Al-2Cr-4Nb-0.3Y(摩尔分数,％)合金薄带破碎成粉末,然后通过等离子烧结(SPS)制备成块体.研究烧结温度对烧结块体的组织和力学性能的影响.在1200℃烧结时得到完全致密的块体.进一步升高烧结温度对合金密度的影响不大,但是对烧结块体的显微组织及相结构有显著影响.烧结块体主要由γ和α2相组成,随着烧结温度的升高,α2相的体积分数降低,块体合金由近γ组织演变为近层片组织,且组织逐渐粗化,但是长大不明显.1260℃烧结得到的块体组织细小、均匀,没有明显微偏析,具有良好的综合力学性能,室温压缩断裂强度和压缩率分别为2984 MPa和41.5％,高温(800℃)拉伸断裂强度和伸长率分别为527.5 MPa和5.9％.
장쾌속응고Ti-46Al-2Cr-4Nb-0.3Y(마이분수,％)합금박대파쇄성분말,연후통과등리자소결(SPS)제비성괴체.연구소결온도대소결괴체적조직화역학성능적영향.재1200℃소결시득도완전치밀적괴체.진일보승고소결온도대합금밀도적영향불대,단시대소결괴체적현미조직급상결구유현저영향.소결괴체주요유γ화α2상조성,수착소결온도적승고,α2상적체적분수강저,괴체합금유근γ조직연변위근층편조직,차조직축점조화,단시장대불명현.1260℃소결득도적괴체조직세소、균균,몰유명현미편석,구유량호적종합역학성능,실온압축단렬강도화압축솔분별위2984 MPa화41.5％,고온(800℃)랍신단렬강도화신장솔분별위527.5 MPa화5.9％.
A TiAl alloy from pulverized rapidly solidified ribbons with the composition of Ti-46Al-2Cr-4Nb-0.3Y (mole fraction,％) was processed by spark plasma sintering (SPS).The effects of sintering temperature on the microstructure and mechanical properties were studied.The results show that the microstructure and phase constitution vary with sintering temperature.Sintering the milled powders at 1200 ℃ produces fully dense compact.Higher sintering temperature does not improve the densification evidently.The dominant phases are γ and α2 in the bulk alloys sintered at 1200 ℃.With higher sintering temperature,the fraction of α2 phase decreases and the microstructure changes from equiaxed near γ grain to near lamellar structure,together with a slight coarsening.The bulk alloy sintered at 1260 ℃ with refined and homogeneous near lamellar structure reveals the best overall mechanical properties.The compressional fracture stress and compression ratio are 2984 MPa and 41.5％,respectively,at room temperature.The tensile fracture stress and ductility are 527.5 MPa and 5.9％,respectively,at 800 ℃.