Abstract To avoid the “susceptibility artifacts” in magnetic resonance imaging (MRI) and realize patient-specific medical devices with complicated shapes, a novel MRI compatible Zr-1Mo alloy with low porosity (c.a. 0.4%) were manufactured by laser powder bed fusion process(L-PBF) using gas-atomized Zr-1Mo(wt%) alloy powder. However, as-built Zr-1Mo(wt%) components using optimized process parameters show relatively high mechanical performance(elongation of 6.4%, UTS of 1175 MPa), but contain 0.4 vol% defects which show a spherical morphology and distribute in the builds randomly. These defects definitely deteriorate the mechanical performance(especially ductility, fatigue behavior) of Zr-1Mo components manufactured by L-PBF. In order to eliminate defects in as-built Zr-1Mo components, hot isostatic pressing(HIP), which has been known as an effective process to decrease the porosity of additive manufactured products, was executed. Due to the elevated temperature and high pressure during HIP treatment, the randomly distributed defects were eliminated after the HIP process. Moreover, the α-martensite structure in the as-built alloy was transformed into a basketweave α + β structure at low HIP temperature(1023 K and 1073 K) or lamellar α + β structure at relatively high HIP temperature(1173 K and 1273 K). In the meantime, the elongation of HIP-treated Zr-1Mo components significantly increased, but the strength shows the opposite trend. From the viewpoint of mechanical property, Zr-1Mo components HIP-treated at 1023 K possessed elongation of 19.9%, and UTS of 628 MPa should be optimized in this study. More importantly, porosity regrowth behavior was investigated to evaluate subsequent heat treatment feasibility for further improvement of mechanical performance. Due to intact raw material power as well as vacuum/low pressure inside the original defect caused by evaporation of metals, porosity regrowth can not be confirmed in HIP-treated Zr-1Mo components after subsequent heat treatment(holding temperature higher than the β transus of Zr-1Mo alloy). Therefore, further improvement of mechanical performance by subsequent heat treatment for HIP-treated Zr-1Mo components is very promising and should conduct further research in the future

中文翻译：

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激光粉末床融合制造的 MRI 兼容 Zr-1Mo 部件的热等静压

摘要 为避免磁共振成像 (MRI) 中的“磁敏感伪影”并实现形状复杂的患者特异性医疗器械，采用激光粉末床融合工艺制造了一种低孔隙率 (ca 0.4%) 的新型 MRI 兼容 Zr-1Mo 合金。 (L-PBF) 使用气雾化 Zr-1Mo(wt%) 合金粉末。然而，使用优化工艺参数的 Zr-1Mo(wt%) 组件显示出相对较高的机械性能（伸长率为 6.4%，UTS 为 1175 MPa），但包含 0.4 vol% 的缺陷，这些缺陷显示出球形形态并分布在构建中随机。这些缺陷肯定会降低 L-PBF 制造的 Zr-1Mo 部件的机械性能（尤其是延展性、疲劳行为）。为消除 Zr-1Mo 组件中的缺陷，热等静压（HIP），已被公认为减少增材制造产品孔隙率的有效工艺。由于 HIP 处理过程中的高温和高压，HIP 处理后消除了随机分布的缺陷。此外，在低HIP温度（1023 K和1073 K）下，合金中的α-马氏体组织转变为篮织α+β结构或在较高HIP温度（1173 K和1273 K）下转变为层状α+β结构。 ）。同时，HIP 处理的 Zr-1Mo 部件的延伸率显着增加，但强度却呈相反趋势。从力学性能的角度来看，在 1023 K 下 HIP 处理的 Zr-1Mo 部件具有 19.9% 的伸长率，本研究应优化 628 MPa 的 UTS。更重要的是，研究了孔隙率再生长行为，以评估后续热处理的可行性，以进一步提高机械性能。由于原料功率完整，以及金属蒸发引起的原始缺陷内部的真空/低压，在后续热处理（保持温度高于 β 转变温度）后，HIP 处理的 Zr-1Mo 部件无法确认孔隙再生长。 Zr-1Mo合金）。因此，对经过 HIP 处理的 Zr-1Mo 部件通过后续热处理进一步提高机械性能是非常有前景的，未来应该进一步研究 在随后的热处理（保持温度高于 Zr-1Mo 合金的 β 转变温度）后，在 HIP 处理的 Zr-1Mo 部件中无法确认气孔再生长。因此，对经过 HIP 处理的 Zr-1Mo 部件通过后续热处理进一步提高机械性能是非常有前景的，未来应该进一步研究 在随后的热处理（保持温度高于 Zr-1Mo 合金的 β 转变温度）后，在 HIP 处理的 Zr-1Mo 部件中无法确认气孔再生长。因此，对经过 HIP 处理的 Zr-1Mo 部件通过后续热处理进一步提高机械性能是非常有前景的，未来应该进一步研究