α相织构对激光沉积制造TC4合金力学行为影响研究

Effect ofαTexture on Mechanical Behavior of TC4 Alloy Fabricated by Laser Deposition Manufacturing

为探明激光沉积制造TC4合金拉伸性能各向异性产生的机制,对不同取样角度的试样进行拉伸性能测试,并采用电子背散射衍射技术对成形件的晶体取向进行分析。结果表明:90°试样(拉伸试样的长轴方向与水平方向夹角为90°)的延伸率比45°试样高32%,抗拉强度和屈服强度分别低9%和8%;90°试样中的主要织构所对应的Schmid因子值最高,为0.485,外加拉伸应力σ与滑移方向分切应力τ之间的夹角θ为38°,试样首先开动的滑移系为柱面滑移系;45°试样的Schmid因子值最低,为0.415,θ为28°,试样首先开动的滑移系是锥面滑移系;90°试样中小角度晶界的占比最小,为1%,45°试样中小角度晶界的占比最高,为29.2%;90°试样具有最优的塑性,而45°试样具有最高的强度。

To investigate the generation mechanism of anisotropy of tensile properties,we tested the tensile properties of samples from different sampling angles and analyzed the crystal orientation of formed parts using electronic back-scattering diffraction.The results demonstrate that the elongation of the 90°sample(angle between the long axis direction of the tensile sample and the horizontal direction is 90°)is 32%higher than that of the 45°sample,and the tensile strength and yield strength are 9%and 8%lower,respectively.The Schmid factor corresponding to the 90°sample′s main texture has the highest value of 0.485,and the angleθbetween external tensile stressσand shear stress along the sliding directionτis 38°.The first moving slip system is a prismatic slip system.The Schmid factor of the 45°sample is the lowest(0.415),andθis 28°.The first slip system of the sample is a pyramidal slip system.The 90°sample has the smallest proportion of small angular grain boundaries(1%),whereas the 45°sample has the highest proportion(29.2%).Additionally,the 90°sample has optimal plasticity,whereas the 45°sample has the highest strength.