Preparation of TiZrNbTa refractory high-entropy alloy powder by mechanical alloying with liquid process control agents

• Published in: Intermetallics 2020-11, Vol.126, p.106900, Article 106900
• Main Authors: Qiao, Yating, Tang, Yu, Li, Shun, Ye, Yicong, Liu, Xiyue, Zhu, Li'an, Bai, Shuxin
• Format: Article
• Language: English
• Subjects: Alloy development; Alloy powders; Cold welding; Crystal defects; Ethanol; Heptanes; High entropy alloy; High entropy alloys; High resistance; High temperature; Homogeneity; Mechanical alloying; Morphology; n-heptane; Process control agent; Process controls; Radiation tolerance; Shear forces; Stearic acid; TiZrNbTa
• ISSN: 0966-9795; 1879-0216
• DOI: 10.1016/j.intermet.2020.106900

The development and applications of refractory high-entropy alloys (RHEAs) have garnered attention for their outstanding strength at both room and elevated temperatures and their high resistance to radiation. However, certain issues have posed difficulty in its preparation and resulting quality. Thus, this study proposed and verified a method to improve the quality of RHEA powders prepared by mechanical alloying by adding liquid process control agents (PCAs). Mechanical alloying was investigated without a PCA and with solid (stearic acid) and liquid PCAs (ethanol and n-heptane). The results showed that the liquid PCAs effectively mitigated cold welding. Relative to those of the powders processed without a PCA or with a solid PCA, the recovery ratio of the powders with liquid PCAs significantly increased, i.e., from 5% to 90%. Moreover, the powders produced with liquid possessed an ideal composition similar to that of the designed product. Adding a liquid PCA did not alter the processes of morphology evolution, element inter-diffusion, and structural transformation. The liquid environment increased the efficiency of the particle refinement and element diffusion, thus increasing the homogeneity of the elemental distribution. The presence of the amorphous phase and C/O interstitial contamination were minimal, owing to the maximum limiting value of lattice defects caused by the shear force in the liquid environment. Therefore, the liquid PCA improved the quality of RHEA powders prepared by mechanical alloying. [Display omitted] •Liquid process control agents (PCA) were used in TiZrNbTa RHEA powder mechanical alloying.•Compared to solid or no PCA, liquid PCA improved the recovery ratio from 5 to 90%.•Liquid environment improved the homogeneity of the elemental distribution.•Few amorphous phase and C/O interstitial contamination can be effectively avoided.