The hot deformation behavior of a Ti-47Al-2Cr-2Nb-0.2W-0.15B （at%） titanium aluminide alloy fabricated by pre-alloyed powder metallurgy has been investigated by using the hot compression tests in the temperature range from 950℃ to 1300℃ and at the strain rates between 10-3 s-1 and 10 s-1. The processing maps have been established to evaluate the optimum hot processing conditions and reveal the instability regions. It is found that the flow stress of the investigated alloy is a strong function of the temperature and the strain rate, The investigated alloy has the optimum hot-working condition at 950℃ and 10-3 s-1, since the material undergoes dynamic recrystallization to produce a fine-grained microstructure. At 1250℃ and 10-3 s-1, the alloy exhibits superplastic deformation. At 2300℃ and 10-1 s-1, the cyclic dynamic recrystallization with high temperature grain coarsening takes place. The material undergoes flow instabilities at lower temperatures and higher strain rates, as predicted by the instability criterion. The processing maps demonstrate that the strain significantly affected the instability regions. The manifestations of the instabilities have been observed in the form of microvoids, wedge cracks, and surface fractures.
参考文献
| [1] | M. THOMAS;O. BERTEAUX;F. POPOFF .Effects of exposure at 700 deg C on RT tensile properties in a PM - gamma -TiAl alloy[J].Intermetallics,2006(10/11):1143-1150. |
| [2] | A. LASALMONIE .Intermetallics: Why is itso difficult to introduce them in gas turbine engines?[J].Intermetallics,2006(10/11):1123-1129. |
| [3] | R.M. Imayev;V.M. Imayev;M. Oehring .Alloy design concepts for refined gamma titanium aluminide based alloys[J].Intermetallics,2007(4):451-460. |
| [4] | R. Gerling;H. Clemens;F. P. Schimansky .Power Metallurgical Processing of Intermetallic Gamma Titanium Aluminides[J].Advanced Engineering Materials,2004(1/2):23-38. |
| [5] | Y.V.R.K. Prasad;D.H. Sastry .Processing maps for hot working of a P/M iron aluminide alloy[J].Intermetallics,2000(9/11):1067-1074. |
| [6] | S. Anbuselvan;S. Ramanathan .Hot deformation and processing maps of extruded ZE41A magnesium alloy[J].Materials & design,2010(5):2319. |
| [7] | S. L. Semiatin;V. Seetharaman .A criterion for intergranular failure during hot working of a near-gamma titanium aluminide alloy[J].Scripta materialia,1997(3):291-297. |
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