离心铸造TC4合金冷速对其组织和力学性能的影响

Effect of cooling rate on structure and tensile strength of centrifugally cast TC4 alloy in ceramic-shell mold

实验与模拟计算相结合研究Ti-6Al-4V(TC4)合金在陶瓷壳型离心精铸条件下,铸件模数对凝固过程冷速的影响,以及铸件组织、性能随模数和冷速之间的统计关系。结果表明:当铸件模数较小时,模数大小对凝固过程冷速影响比较显著,而随着模数的进一步增加,当M>7.00mm时,铸件冷却速度随模数变化并不明显;晶粒尺寸、α/β片层厚度及二次枝晶间距均随铸件模数的增加及冷速的减小而增大,抗拉强度则呈现相反趋势。得出了TC4离心精铸件组织、性能与铸件模数和冷速之间定量关系的表达式。

Both the experimental analyses and computer simulation were conducted to determine the statistical relationship between the structures and mechanical properties of centrifugally cast TC4 alloy in ceramic-shell mould.The results show that,when the cast modulus（M） is smaller,the modulus has significant influence on the cooling rate.But with increasing modulus,the influence of modulus on the cooling rate is weakened while M is larger than 7.00 mm.The grain size,α/β lamellar thickness and secondary dendrite arm spacing all increase with increasing the casting module or decreasing the cooling rate,while the tensile strength varies in an opposite changing manner.The regression functions for the corresponding relationships are given according to the present investigations.