Additive manufacturing of WMoTaTi refractory high-entropy alloy by employing fluidised powders
Additive manufacturing of WMoTaTi refractory high-entropy alloy by employing fluidised powders
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DOI：
10.1080/00325899.2022.2031718
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发表时间：
2022-01-28
影响因子：
1.4
通讯作者：
Qu, Xuanhui
中科院分区：
文献类型：
--
作者：
Liu, Chang;Zhu, Keyan;Qu, Xuanhui
在本研究中，以预合金粉末为原料，采用机械铣磨结合气固流化的方法，成功制备了WMoTaTi难熔高熵合金。流态化有效地提高了颗粒的球形度，使其扩散性能更适合于SLM。从激光功率、孵化空间、扫描速率等方面对加工参数进行了研究。SLM （SLMed）制备的WMoTaTi的相对密度为95.8 +/- 1.4%，以BCC相为主，HCP相较少。超快冷却过程中凝固不平衡导致HCP Ti的少量析出。通过SLM制备的WMoTaTi的显微硬度为617.2 +/- 4.1 HV，优于传统工艺制备的WMoTaTi显微硬度。细小的晶粒尺寸和纳米级的HCP析出有利于位错钉住，提高了强度，形成了良好的显微硬度。这项工作表明，在使用成本合理的流化预合金粉末时，SLMed WMoTaTi具有良好的机械性能。
In this study, WMoTaTi refractory high-entropy alloy was successfully fabricated via selective laser melting (SLM) using pre-alloyed powders by mechanical milling combined with gas-solid fluidisation. Fluidisation effectively improves the particle sphericity and thus its spreading performance suitable for SLM. Processing parameters were investigated in terms of laser power, hatching space and scanning rate. The relative density of WMoTaTi made by SLM (SLMed) reaches 95.8 +/- 1.4%, and it consisted of dominant BCC phase and minor HCP phase. The slight precipitation of HCP Ti was driven due to the non-equilibrium solidification during ultra-rapid cooling by SLM. The microhardness of WMoTaTi via SLM is 617.2 +/- 4.1 HV, preferable to those fabricated by traditional manufacturing processes. The sound microhardness is resulted from the fine grain size and nano-sized HCP precipitates, which favour dislocation pinning and promote strength. This work demonstrates that SLMed WMoTaTi has sound mechanical properties while using the cost-affordable pre-alloyed powders by fluidisation.