Effect of content and configuration of equiaxed α and lamellar α on deformation mechanism and tensile properties of a near-α titanium alloy
Effect of content and configuration of equiaxed α and lamellar α on deformation mechanism and tensile properties of a near-α titanium alloy
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DOI：
10.1016/j.msea.2023.145192
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发表时间：
2023-05
期刊：
影响因子：
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通讯作者：
Yu Zhou;Ke Wang;Honghui Li;Xin Wen;R. Xin
中科院分区：
文献类型：
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作者：
Yu Zhou;Ke Wang;Honghui Li;Xin Wen;R. Xin
本工作制备了全等轴组织、魏德曼组织、篮纹组织和双峰组织，系统研究了等轴α（αe）含量和α片层构型对近α钛合金变形机制和拉伸性能的影响。由αe和平行α片层（α集落）组成的双峰微结构（BM）表示为BMC，而含有αe和篮纹α片层（α篮纹）的BM表示为BMB。随着αe含量的降低，BMB比BMC具有更高的强度增量和更低的伸长率降低。在相同αe含量下，BMB比BMC具有更高的强度和更好的延伸率。同时，αe含量为15%的BMB可以实现高强度和良好延伸率的良好结合。通过原位拉伸试验和 TEM 表征研究了全等轴微观结构 (FEM)、BMC 和 BMB 的变形机制。研究发现，三种微观结构中，棱柱滑移是主导的滑移系统，而棱柱滑移的位错增殖在所有α晶粒中占主导地位。 α可以很好地协调变形以有利于伸长率，而α颗粒中的长滑移长度会相当程度地降低强度。几何兼容性计算表明，α篮纹组织比α群能够更好地抑制滑移传递，从而导致BMB和篮纹组织具有更高的强度。此外，BMB 中连续 αGB 和篮纹微观结构的缺失可以促进更好的伸长率。
This work fabricated fully equiaxed, Widmanstätten, basketweave and bimodal microstructures to systematically investigate the influence of content of equiaxed α (αe) and configuration of α lamellas on the deformation mechanism and tensile properties of near-α titanium alloy. The bimodal microstructures (BMs) comprised of αeand parallel α lamellas (α colony) is denoted as BMC, while the BMs containing αeand basket-weave α lamellas (α basketweave) is denoted as BMB. With the decreasing content of αe, BMB has the higher increment of strength and lower reduction of elongation than BMC. Under the same content of αe, BMB has the higher strength and better elongation than BMC. Meanwhile, BMB with αecontent of 15% could achieve a good combination of high strength and good elongation. The deformation mechanisms of fully equiaxed microstructure (FEM), BMC and BMB were investigated by in-situ tensile tests and TEM characterization. It is found that prismatic slip is the dominant slip system initiated in the three microstructures, while the dislocation multiplication of prismatic slip dominates all the αegrains. The αecould well coordinate deformation to benefit the elongation whereas the long slip length in αegrains could fairly degrade the strength. The calculation of geometry compatibility indicates α basketweave could better restrain slip transfer than α colony, which leads to the higher strength of BMB and basketweave microstructure. Moreover, the absence of continuous αGBin BMB and basketweave microstructure could promote a better elongation.