Solid state phase transformation characteristics of the body centred β(Ti)into the hexagonal closed packed α(Ti)in Ti45AISNb-(0,0.3,0.5 and 0.8 at.pct)B alloys were investigated by heat treatment to clarify γ/α2 lamellar microstructure refinement induced by B addition.Experimental results confirmed two kinds of boron-reduced grain refinement mechanisms through refining either β phase then α phase(β-refinement)or α phase directly(α-refinement)to refine lamellar microstructure at room temperature; however,the role of α-refinement dominated the as-cast lamellar microstructure refinement over β-refinement in Ti45A18NbxB alloy.It was also found that during the α-refinement the convoluted flake-and plate-like borides along β grain boundaries assisted nucleation of α phase,and the particle-like borides near β grain boundaries impeded αphase growth.
参考文献
| [1] | U. Kitkamthorn;L.C. Zhang;M. Aindow .The structure of ribbon borides in a Ti-44Al-4Nb-4Zr-lB alloy[J].Intermetallics,2006(7):759-769. |
| [2] | U. Hecht;V. Witusiewicz;A. Drevermann .Grain refinement by low boron additions in niobium-rich TiAl-based alloys[J].Intermetallics,2008(8):969-978. |
| [3] | Y. Wang;J.N. Wang;J. Yang .Control of a fine-grained microstructure for cast high-Cr TiAl alloys[J].Materials Science & Engineering, A. Structural Materials: Properties, Misrostructure and Processing,2005(1/2):235-239. |
| [4] | R.M. Imayev;V.M. Imayev;M. Oehring .Alloy design concepts for refined gamma titanium aluminide based alloys[J].Intermetallics,2007(4):451-460. |
| [5] | A. K. Singh;K. Muraleedharan;D. Banerjee .Solidification structure in a cast γ alloy[J].Scripta materialia,2003(6):767-772. |
| [6] | S. TAMIRISAKANDALA;R. B. BHAT;J. S. TILEY .Grain Refinement of Cast Titanium Alloys Via Trace Boron Addition[J].Scripta materialia,2005(12):1421-1426. |
| [7] | C.Angelier .Building a Continuous Cooling Transformation Diagram ofβ-CEZ Alloy by Metallography and Electrical Resistivity Measurements[J].Metallurgical and Materials Transactions, A. Physical Metallurgy and Materials Science,1997(12):2467-2476. |
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