Abstract：The TiAl-based alloy with nominal composition of Ti-44Al-4Nb-2(Mo,Cr,B,Y) was studied. Effect of heat treatment temperature and time on microstructure and microhardness of TiAlNbCr alloy was also discussed. It can be concluded that the eutectoid transformation (α2+γα) temperature was found at 1 17923 ℃ through differential scanning calorimetry(DSC) test. And when the alloy was undergoing the heat-treatment at the temperature near the eutectoid transformation (α2+γα) temperature, the lamellar structure was degrading and at the same time the γ,α and B2 grains were growing and spheroidizing. It can also be concluded that after aging at 1 200 ℃ for 15 min following 1 h solid solution, the as-cast alloy obtained precipitation strengthening and had peak value of microhardness.
宋睿瑾. 热处理对Ti-44Al-4Nb-2(Mo,Cr,B,Y)合金显微组织与硬度的影响[J]. , 2015, 22(1): 48-52.
SONG Rui-jin. Effects of heat treatment on the microstructure and microhardness of Ti-44Al-4Nb-2 (Mo,Cr,B,Y) alloys. , 2015, 22(1): 48-52.
F. Appel, R.Wagner, Microstructure and deformation of two-phase γ-titanium aluminides[J]. Materials Science and Engineering, 1998. 22(5): 187-267
[6]
S.L. Semiatin, V. Seetharaman, V.K. Jain, Microstructure Development during Conventional and Isothermal Hot Forging of a Near-Gamma Titanium Aluminide[J]. Metallurgical and material stransactions, 1994. 25A:2753-2768
[7]
Veeraraghavan D.,Vijay K.,Vasudevan,Phase transformations in two-phase TiAlTi3Al alloys during continuous heating and cooling, studied by electrical resistivity measurements[J]. Materials Science and Engineering: A, 1995. 192(1993): 950-955
[8]
Fusheng Sun, Chunxiao Cao, Seungeon Kim, YongTailee,Minggao Yan, Alloying Mechanism of Beta Stabilizers in a TiAl Alloy[J]. Metallurgical and materials transactions, 1997. 32(A): 1574-1590
[9]
Masao Takeyamaa, S.K., Physical metallurgy for wrought gamma titanium aluminides- Microstructure control through phase transformations[J]. Intermetallics, 2005. 13(9):993-999
[10]
Y.Y. Chen, B.H.Li, F.T.Kong, Microstructural refinement and mechanical properties of Y-bearing TiAl alloys[J]. Journal of Alloys and Compounds, 2008. 457:265-269
[11]
F.Appel, Jonathan D.H.Paul, Michael Oehring, Gamma Titanium Aluminide Alloys[M],Science and Technology,2011.
[12]
H. Clemens, H.F. Chladil, W. Wallgram , G.A. Zickler etc, In and ex situ investigations of the b-phase in a Nb and Mo containing γ-TiAl based alloy[J]. Intermetallics, 2008. 16(6): 827-833
[13]
Tetsui T., Development of a TiAl turbocharger for passenger vehicles[J]. Materials Science and Engineering, 2002. A(329-331): 582-588
[14]
F.Appel, M. Oehringa, R. Wagnerb, Novel design concepts for gamma-base titanium aluminide alloys[J]. Intermetallics, 2000. 8(9-11): 1283-1312
[15]
Hanliang Zhu, K.Maruyama, J. Matsuda, Microstructure refinement mechanism by controlling heating process in multiphase materials with particular reference to γ-TiAl[J]. Applied Physics Letters, 2006. 88(131908): 1-3
[16]
H.Z Niu, Y.Y. Chen, S.L. Xiao, and L.J. Xu, Microstructure evolution and mechanical properties of a novel beta γ-TiAl alloy[J]. Intermetallics, 2012. 31(0): p. 225-231.
[17]
M Goken, M Kempf, WD Nix, Hardness and modulus of the lamellar microstructure in PST-TiAl studied by nanoindentations and AFM[J]. Acta Mater, 2001. 49(5):903-911
[18]
Y.Y Chen, H.Z Niu, F.T Kong,S. Xiao, Microstructure and fracture toughness of a γ phase containing TiAl alloy[J]. Intermetallics, 2011. 19(10): 1405-1410.
[19]
Hanliang Zhu, D.Y.Seo, Maruyama Kouichi, Strengthening of lamellar TiAl alloys by precipitation bands of βo particles[J]. Materials Science and Engineering: A, 2009. 510-511(0): 14-19.
2015, Vol. 22 
