RESEARCH ON LASER SOLID FORMING OF A FUNCTIONALLY GRADED TI-TI2ALNB ALLOY
;LIN Xin;LV Xiaowei LV;Jing Chen;Weidong Huang
西北工业大学凝固技术国家重点实验室
Cite this article:
LIN Xin; LV Xiaowei LV; Jing Chen; Weidong Huang. RESEARCH ON LASER SOLID FORMING OF A FUNCTIONALLY GRADED TI-TI2ALNB ALLOY. Acta Metall Sin, 2008, 44(8): 1006-1012 .
Abstract A functionally graded Ti-Ti2AlNb alloy, which had continuous compositional gradient and regular outline with a length of ~17 mm, was fabricated by laser solid forming. Phase morphological evolution and microstructure evolution, and microhardness along the compositional gradient direction were analyzed. With the increase of aluminum and niobium contents, a series of phase evolutions along the compositional gradient occurred: α'→α+β→α+α'→α'→α+β→ α+β/B2+α2→ β/B2+α2→ β/B2→ B2+α2+O→ B2, and the compositionally graded material accomplished a transition of α titanium alloy, α+β titanium alloy, β titanium alloy, finally ended with Ti2AlNb-based alloy. In the transition layers, The microhardness increased from 170HV with CP titanium at the bottom to 470HV with Ti2AlNb at the top. Based on the non-equilibrium phase diagram of the Ti-rich corner, the phase morphological evolution during laser solid forming of the graded materials were explained on combining with the analysis of the influence of the Al, Nb on the stability of α，β and α2 phases in titanium alloys.
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