Ti-Mo-xTiC composites manufactured by U-FAST reactive sintering

• Published in: International journal of refractory metals & hard materials 2022-11, Vol.108, p.105960, Article 105960
• Main Authors: Figiel, Paweł, Biedunkiewicz, Anna, Jach, Katarzyna, Obrosov, Aleksei, Garbiec, Dariusz, Bik, Maciej, Sitarz, Maciej, Kucia, Zofia, Pawlyta, Mirosława, Weiß, Sabine
• Format: Article
• Language: English
• Subjects: EBSD; Nanoindentation; SPS; TiMMCs; Wear
• ISSN: 0263-4368; 2213-3917
• DOI: 10.1016/j.ijrmhm.2022.105960

The paper presents the characteristics of Ti-Mo-xTiC composites manufactured under experimentally selected conditions using the upgraded field-assisted sintering technique (U-FAST). Mixtures of microstructural titanium powders and nc-Ti0.9Mo0.1C/C carbide powders protected from oxidation by a carbon shell were subjected to sintering. The powders with nc-Ti0.9Mo0.1C/C contents of 10 and 20 wt% were used. The content of carbon forming the carbon shell was approximately 3 or 40 wt%. Composites with near full density were reinforced with titanium carbides in a Ti-Mo matrix. The composites with the highest content of reinforcing phase are characterized by the highest values of hardness, Young's modulus and wear resistance. Although the hardness of these composites is similar to that of ceramics, their nature is not brittle. Despite the high value of the Young's modulus, the addition of hard particles of the reinforcing phase to the titanium matrix significantly increases the values of the H/E ratio of the composites compared to the reference samples of cp-Ti and Ti6Al4V. A comparison of the research results for the composites with the highest share of titanium carbides showed that lowering the sintering temperature from 1300 to 1150 °C resulted in the inhibition of grain growth, a reduction in composite heterogeneity, composite roughness and hardness as well as a rise in the Young's modulus. An increase in the sintering temperature from 1150 to 1300 °C contributed to the higher high angle grain boundaries (HAGB) content. •The application of U-FAST technique enables nearly full densification of the Ti-Mo-xTiC composites•The carbon shell surrounding the nanocrystalline MoxTi1-xC/C protects them against oxidation•(Ti,Mo)C carbide undergoes spinodal decomposition into two carbides, i.e. TiC and MoC, and then the MoC reacts with titanium matrix•Composites with the highest reinforcing phase content had the highest values of hardness, Young's modulus and wear resistance