Abstract In this study, the bimodal Ti-xBi (x = 0, 0.5, 1, 3 and 5 at.%) alloys were fabricated using mechanical alloying (MA) and spark plasma sintering (SPS) from elemental powders. The microstructure evolution of mechanical alloyed (MAed) powders as well as the effect of Bi content on microstructure and mechanical properties of Ti-Bi alloys are investigated. The Ti-Bi alloys showed bimodal structure consisting coarse grains (CG) region in “core” and ultrafine grains (UFG) region in “shell”. The Ti-Bi matrix was α-Ti with hexagonal close-packed (HCP) structure while Bi-riched phase was identified as β-Ti with body-centered cubic (BCC) structure. The mechanical properties showed that the as-built bimodal alloys had high strength and large plastic deformation. The Ti-Bi alloys showed ~22%–44% higher compressive yield strength compared with commercially pure Ti (CP-Ti) alloy for same the ball-milling time, and strengthening mechanisms are mainly ascribed to grain boundary strengthening and solid solution strengthening. When Bi content was 0.5%, the alloy exhibited excellent comprehensive mechanical properties with high compressive strength (compressive yield strength of ~1080 MPa, ultimate compressive strength of ~2226 MPa) and excellent ductility (fracture strain of ~34.3%).

中文翻译：

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通过机械合金化和放电等离子烧结制备的双峰 Ti Bi 合金的显微组织和机械性能用于生物医学应用

摘要 在本研究中，使用机械合金化 (MA) 和放电等离子烧结 (SPS) 从元素粉末制备双峰 Ti-xBi (x = 0, 0.5, 1, 3 和 5 at.%) 合金。研究了机械合金化 (MAed) 粉末的微观结构演变以及 Bi 含量对 Ti-Bi 合金微观结构和机械性能的影响。Ti-Bi合金显示出双峰结构，包括“核”中的粗晶粒（CG）区域和“壳”中的超细晶粒（UFG）区域。Ti-Bi 基体是具有六方密堆积 (HCP) 结构的 α-Ti，而富 Bi 相被确定为具有体心立方 (BCC) 结构的 β-Ti。力学性能表明，所制备的双峰合金强度高，塑性变形大。在球磨时间相同的情况下，Ti-Bi 合金的压缩屈服强度比商业纯 Ti (CP-Ti) 合金高约 22%–44%，强化机制主要归因于晶界强化和固溶强化。当Bi含量为0.5%时，该合金表现出优异的综合力学性能，具有高抗压强度（压缩屈服强度~1080 MPa，极限抗压强度~2226 MPa）和优异的延展性（断裂应变~34.3%）。