快速凝固Ti_3Al基合金的显微组织

MICROSTRUCTURE OF RAPIDLY SOLIDIFIED Ti_3Al-BASE ALLOYS

研究了Ｔｉ_３Ａｌ及Ｔｉ_３Ａｌ─Ｎｂ合金的快速凝固组织．结果表明，快速凝固组织和铸态组织及热处理组织比较有很大变化．合金经过快速凝固后显微组织明显细化，Ｄ０_（１９）结构转变为有序斜方马氏体（α″）；加入强β稳定化元素Ｎｂ的Ｔｉ_３Ａｌ基合金，快速凝固组织依加入Ｎｂ量的不同，依次出现α″，α″＋β_０和β_０组织，并且β_０相中的反相畴得到明显细化．

The microstructure of RS Ti_3Al-base alloys prepared by the hammer-and-anvil technique has been studied. The as-RS microstructures of the alloys are quite different to the as-cast one. First, the grains of the RS alloys are finer. Secondly, the Ti_3Al-base alloys with D0_(19) structure in normal condition have transformed fully into ordering orthogonal martensite α″in the RS microstructure. And then, α″,α″+β0, or β0 has been observed sequentially in the RS Ti_3Al-Nb alloys according to the addition of Nb,the strong β-isomorphous stabilizer of Ti,and the APBs in β0 in the RS Ti_3Al-Nb alloy are finer.