摘要
研究了B含量分别为0.2%和1.0%(原子分数)两种TiAl合金中TiB2相的生长机制,结果表明G2(Ti-47.5Al-5(Cr,Nb,W,Si)+1.0B%)合金中少量TiB2相是由于成分起伏从液相中生成的初生块状TiB2相,大部分TiB2相是在凝固过程与β相共同耦合生长的次生带状、杆状TiB2相;G1(Ti-47.5Al-5(Cr,Nb,W,Si)+0.2B%)合金中TiB2相是由共晶反应生成的次生带状TiB2相。G2合金全片层组织和网篮组织室温塑性均优于G1合金,网篮组织室温强度与G1合金相当,而全片层组织室温强度却不如G1合金。在760℃/100 MPa/200 h蠕变条件下G2合金全片层组织残余蠕变量和蠕变速率均低于G1合金。
The growth mechanisms of TiB2 phases in 0.2%B contained TiAl alloys（G1） and 1.0%B contained TiAl alloys（G2） were investigated.The results show that a few amounts of primary blocky TiB2 phases in G1 alloy are generated from liquid phase as a result of constitutional fluctuation,while most amounts of TiB2 phases are ribbony and flaky morphology secondary TiB2 phase forming with the matrix β phase during the solidification.TiB2 phases in G1 alloy are secondary ribbony morphology TiB2,which are mainly eutectic reaction products.G2 alloy presents superior room temperature tensile elongation to that of both fully lamellar and basket-weave microstructure G1 alloy.The tensile strength of basket-weave microstructure G2 alloy is comparable to G1 alloy,but fully lamellar microstructure G2 alloy has lower tensile strength than G1 alloy.Creep strain and creep rate of full-lamellar G2 alloy is lower than that of G1 alloy at 760 ℃.
出处
《稀有金属》
EI
CAS
CSCD
北大核心
2012年第3期347-352,共6页
Chinese Journal of Rare Metals
基金
国防预研基金项目资助(51412010304HK5110)
