2020/08/31 by Samuel A. Humphry-Baker, Humphry-Baker, Samuel A., Luc Vandeperre +1
Engineering · #Advanced materials and composites #FOS: Physical sciences #Materials Science (cond-mat.mtrl-sci) #Powder Metallurgy Techniques and Materials #Tunneling and Rock Mechanics
paper · pdf · doi:10.48550/arxiv.2008.13565
openalex publication_date 2020/08/31 · openalex created_date 2025/10/10 · openalex updated_date 2026/07/28
Iron is a candidate to replace cobalt in WC hardmetals, due to its lower cost and toxicity. A WC-FeCr hardmetal was compression tested at 900-1200 °C. Particular attention is paid to the steady-state creep rates and stress-exponents (n) during isostress treatments. Three regimes of stress dependence are observed. Two of these were previously reported for WC-Co: power law creep (n~3) at medium stresses; and grain boundary sliding (n~1) at higher stresses, generally >100MPa. A previously unreported low stress (<10MPa) regime with an exponent of n~2 is also observed. By combining electron microscopy with X-ray diffraction texture measurements, the low stress regime is attributed to viscous flow of the binder, which is accommodated by diffusional creep in the WC skeleton. The mechanism may be applicable to other hardmetals. Compared to analogous WC-Co materials, WC-FeCr shows improved creep resistance below 1000 °C, which can be explained by its lower self-diffusivity, and a lower solubility for WC than Co. However, at temperatures corresponding to liquid eutectic formation (~1140 °C), its creep resistance becomes inferior. These results indicate FeCr may be a suitable replacement for Co provided the eutectic temperature is not exceeded.