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Densification behavior, microstructural evolution, and mechanical properties of TiC/316L stainless steel nanocomposites fabricated by selective laser melting
Materials & Design ( IF 7.6 ) Pub Date : 2018-01-01 , DOI: 10.1016/j.matdes.2017.10.039
Bandar AlMangour , Dariusz Grzesiak , Tushar Borkar , Jenn-Ming Yang

Abstract Here we investigate the influence of the volumetric laser energy density (η) utilized in selective laser melting (SLM) on the phase evolution, densification behavior, microstructure evolution, and mechanical properties of TiC/316L stainless steel nanocomposite parts. The η values, which was controlled by adjusting the laser scanning speeds, was found to strongly correlate with the metallurgical mechanisms of the fabricated parts. During the SLM process, low η values induced disordered liquid solidification fronts with significant balling and pore chain defects, which arose from the low-viscosity and highly unstable flow behavior caused by densification-limiting Marangoni convection. Conversely, high η values in SLM significantly enhance densification but induce fine spherical pores and thermal microcracks by increasing liquid lifetimes and thermal stresses. The diffraction angles of the γ-Fe peaks were shifted from their standard locations by the lattice distortion from laser-induced thermal stress. The samples processed at η of 67 J/mm3 showed the most refined microstructures formed under exposure to the highest cooling rates, which led to higher compressive yield strengths than those of samples processed at η of 300 J/mm3. Pole figures obtained for the γ-Fe phase depicted no significant directionality in the texture of any of the components; however, a significant texture intensity increase was reported with increasing η.

中文翻译:

选择性激光熔化制备的 TiC/316L 不锈钢纳米复合材料的致密化行为、微观结构演变和力学性能

摘要 在这里,我们研究了选择性激光熔化 (SLM) 中使用的体积激光能量密度 (η) 对 TiC/316L 不锈钢纳米复合材料零件的相演变、致密化行为、微观结构演变和机械性能的影响。发现通过调整激光扫描速度控制的 η 值与制造零件的冶金机制密切相关。在 SLM 过程中,低 η 值导致无序的液体凝固前沿,具有显着的球化和孔链缺陷,这是由致密化限制 Marangoni 对流引起的低粘度和高度不稳定的流动行为引起的。反过来,SLM 中的高 η 值显着增强了致密化,但通过增加液体寿命和热应力导致细小的球形孔和热微裂纹。由于激光引起的热应力引起的晶格畸变,γ-Fe 峰的衍射角偏离了它们的标准位置。在 67 J/mm3 的 η 下处理的样品显示出在最高冷却速率下形成的最精细的微观结构,这导致比在 300 J/mm3 的 η 下处理的样品更高的压缩屈服强度。为 γ-Fe 相获得的极图显示,任何组件的织构都没有明显的方向性;然而,据报道随着 η 的增加,纹理强度显着增加。由于激光引起的热应力引起的晶格畸变,γ-Fe 峰的衍射角偏离了它们的标准位置。在 67 J/mm3 的 η 下处理的样品显示出在最高冷却速率下形成的最精细的微观结构,这导致比在 300 J/mm3 的 η 下处理的样品更高的压缩屈服强度。为 γ-Fe 相获得的极图表明,任何组件的织构都没有明显的方向性;然而,据报道随着 η 的增加,纹理强度显着增加。由于激光引起的热应力引起的晶格畸变,γ-Fe 峰的衍射角偏离了它们的标准位置。在 67 J/mm3 的 η 下处理的样品显示出在最高冷却速率下形成的最精细的微观结构,这导致比在 300 J/mm3 的 η 下处理的样品更高的压缩屈服强度。为 γ-Fe 相获得的极图显示,任何组件的织构都没有明显的方向性;然而,据报道随着 η 的增加,纹理强度显着增加。为 γ-Fe 相获得的极图显示,任何组件的织构都没有明显的方向性;然而,据报道随着 η 的增加,纹理强度显着增加。为 γ-Fe 相获得的极图显示,任何组件的织构都没有明显的方向性;然而,据报道随着 η 的增加,纹理强度显着增加。
更新日期:2018-01-01
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