Microstructure and mechanical property evolutions of bulk core-shell structured Ti-N alloys during annealing

• Published in: Journal of alloys and compounds 2017-07, Vol.710, p.418-423
• Main Authors: Zhang, Y.S., Zhang, W., Wang, X., Lu, J.W., Zhao, Y.H.
• Format: Article
• Language: English
• Subjects: Annealing; Bulk density; Compression tests; Core-shell structure; Hardening; Mechanical properties; Nitriding; Plastic properties; Sintering; Titanium alloys; Titanium base alloys; Yield strength
• ISSN: 0925-8388; 1873-4669
• DOI: 10.1016/j.jallcom.2017.03.254

Bulk dense core-shell structured Ti-N alloys with three different N contents were synthesized, and then annealed at different temperatures to tailor the mechanical performances. Compression tests show that with increasing N content (nitriding temperature and time), the Ti-N shell thickness and yield strength increase (from 0.9 to 1.2 GPa) with a decrease in fracture plasticity (from 27% to 3%). With increasing annealing temperature, the Ti-N shell thickness and yield strength first increase and then decrease, while fracture plasticity remains unchanged except a dramatic drop at 1500 °C. There exists a linear relationship between the yield strength and shell area fraction indicating the hardening effect of the Ti-N shell. •Core-shell structured Ti-N alloys with three different N contents were synthesized.•Strength, shell thickness increase while plasticity decreases with N content.•Anneal alters microstructure and mechanical performances of the three samples.•Yield strength follows a linear relationship with shell area fraction.