摘要:
通过分析组织和织构研究了Ti75合金板材拉伸性能和冲击韧性的各向异性。结果表明,Ti75板材横向(transverse direction,TD)的抗拉强度、屈服强度、伸长率和冲击韧性均优于轧向(rolling direction,RD)的对应指标。由于板材横向的屈服强度远大于轧向的屈服强度,使得板材横向屈强比(Rp0.2/Rm)远大于轧向的屈强比。Ti75 板材为 $\mathrm{B}/\mathrm{T}$ (basal/transverse) 织构类型, 主要织构组分为 $\{0002\}<11 \overline{2}0>$ (B 织构 $)、\{10 \overline{1} 3\}$ $<11 \overline{2}0>$ (B31 织构) 和 $\{11 \overline{2} 0\}<10 \overline{1} 0>(\mathrm{T}$ 织构), 织构造成横向和轧向拉伸时棱柱面滑移的 Schmid 因子不同。Ti75板材横轧向屈服强度的差异主要与织构引起晶粒滑移系启动的难易不同有关,抗拉强度主要取决于元素的强化作用,主要影响因素的不同造成了板材不同方向屈强比存在较大的差异。
Abstract:
The anisotropy of tensile properties and impact toughness of Ti75 alloy plate were investigated by analyzing the microstructures and textures. The results showed that the ultimate tensile strength,yield strength,elongation and impact toughness in transverse direction( TD) were better than those in rolling direction( RD). Yield strength in transverse direction was much greater than that in rolling direction,therefore,yield ratio in transverse direction was much greater than that in rolling direction.The textures in the rolling Ti75 alloy plate was formed by two components: basal ( B) textures, $\{0002\}<11 \overline{2}0>$ and $\{10 \overline{1} 3\}$ $<11 \overline{2} 0>$ and transverse $(\mathrm{T})$ texture $\{11 \overline{2} 0\}<10 \overline{1}0>$ which led to different Schmid factors in TD and RD tensile tests. The differences of yield strengths in transverse and rolling directions were mainly caused by the slip systems,which were differently activated by different textures,while the tensile strength depended on strengthening effects of elements. Different main influencing factors accounted for the differences of yield ratios in different directions in the Ti75 alloy plate.
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