Design, preparation and study of microstructure, phase evolution and thermal stability of Ti-Co0.35-Cr0.35-Nb-Zr nanocrystalline HEA for biomedical applications

• Published in: Materials today communications 2023-06, Vol.35, p.105557, Article 105557
• Main Authors: Srivastav, Chitrance Kumar, Anuraag, N.Sai, Pandey, Anurag Kumar, Prasad, Nand Kishore, Khan, Debashis
• Format: Article
• Language: English
• Subjects: Alloy Design; Bio-materials; High entropy alloy; Mechanical alloying; Nanocrystalline
• ISSN: 2352-4928; 2352-4928
• DOI: 10.1016/j.mtcomm.2023.105557

In the present study, novel Ti-Co0.35-Cr0.35-Nb-Zr high entropy alloy (HEA) has been synthesized by mechanical alloying (MA) followed by sintering at different temperatures. The microstructure and phase stability of as milled powder and sintered samples have been studied by X-ray diffraction (XRD), scanning electron microscopy (SEM), transmission electron microscopy (TEM) and differential scanning calorimetry (DSC). The density and micro-hardness values have also been calculated for the sintered samples. The atomic % of the individual element is selected based on the parametric method. After 50 h of milling, the powders transformed into a solid solution having BCC structure with a minor fraction of undissolved Zr. The crystallite size (CS) of ∼ 7 nm reveals the nanocrystalline nature of the milled powder. The DSC thermograph displays the phase transformation of the milled powder near ∼ 821 °C. After sintering at 750 °C, the sample had only β (BCC) phase, however, after sintering at 850 and 950 °C, it appeared as both β and α (HCP) phases. Micro-hardness values of the sintered samples have been found to be in the range of 460 – 580 HV which is higher than that of similar biomaterials. This study reveals that Ti-Co0.35-Cr0.35-Nb-Zr HEA can be explored as a new class of biomaterials. [Display omitted]