双相γ＋α2钛合金片层承载力的数学模型及预测

A mathematical model for predicting mechanical properties of Ti-Al alloy with lamellar structures of γ-TiAl+α_2

为了研究双相γ+α2钛合金晶体中片层组织的承载特性,建立了相应晶体不同取向力学性能的数学模型,并计算了γ相及γ+α2片层组织不同取向的承载力.通过对模型的数值求解,得到γ相和γ+α2片层组织的承载力随不同加载方向的变化规律.计算结果表明:随着α2相体积分数的增加,γ+α2片层组织的最大承载力方向逐渐趋向平行于α2相的(0001)面,临界α2相等价体积分数为λe=30%.这从理论上解释了γ+α2片层组织的最大承载力方向为平行于α2相的(0001)面这一传统观点.这一结论成立的条件为α2相等价体积分数λe>30%.

A mathematical model for calculating some mechanical properties of crystal of titanium alloy was established to study the mechanical behavior of γ-TiAl alloys with lamellar structure.By calculating the numerical solution of the model,the change trend of the mechanical properties of the γ-phase and the γ＋α2 lamellar structure was obtained.The results indicat that,with the increase of the amount of α2 phase,the maximum load-bearing direction of the γ＋α2 lamellar structure changes gradually to the direction parallel to（0001） of α2 phase with a critical equivalent volume fraction of λe=0.3.This theoretically explaines the traditional point of view that the maximum load-bearing direction of the γ＋α2 lamellar structure is parallel to the crystal plane（0001） of α2 phase.Furthermore,the results suggest that the traditional point of view is true only when λe〉0.3.