Effect of forging on the microstructure and texture of a high Nb containing γ-TiAl alloy
The effect of forging on the microstructure and texture evolution of a high Nb containing Ti-45Al-7Nb-0.3W(at.%)alloy was investigated by X-ray diffractometer(XRD),scanning electron microscopy(SEM),and transmission electron microscopy(TEM).The results show that the as-cast alloy is mainly composed of α2/γ lamellar colonies with a mean size of 70 μm,but the hot-forged pancake displays a near duplex microstructure(DP).Kinking and bending of lamellar colonies,deformation twinning and dynamic recrystallization(DRX)occur during hot forging.Meanwhile,dense dislocations in the β phase after forging suggest that the high-temperature β phase with a disordered structure is favorable for improving the hot-workability of the alloy.Unlike the common TiAl casting texture,the solidification process of the investigated as-cast alloy with high Nb content is completely via the β phase region,resulting in the formation of a<110>γ fiber texture where the<110>γ aligns parallel to the heat-flow direction.In comparison,the relatively strong<001>and weak<302>texture components in the as-forged alloy are attributed to the deformation twinning.After annealing,static recrystallization occurs at the twin boundary and intersections,which weakens the deformation texture.
high Nb containing γ-TiAl alloyforgingmicrostructuretextureβ phase
陶慧、李慧中、王丽、周睿、车逸轩、陈永辉、梁霄鹏
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School of Materials Science and Engineering,Central South University,Changsha 410083,China
State Key Laboratory of Powder Metallurgy,Central South University,Changsha 410083,China
Key Laboratory of Nonferrous Metal Materials Science and Engineering,Central South University,Changsha 410083,China
Department of Materials Science and Engineering,City University of Hong Kong,Kowloon 999077,Hong Kong,China
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高铌TiAl合金 锻造 显微组织 织构 β相
National Natural Science Foundation of ChinaNational Natural Science Foundation of China
NETL
NSTL
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