Quantification of nano-scale interface structures to guide mechanistic modelling of WC grain coarsening inhibition in V-doped hard metals
Artikel i vetenskaplig tidskrift, 2021

The control of tungsten carbide (WC) grain coarsening using coarsening inhibitors is considered to be one of the most important advancements for hard metals, leading to metal cutting tools with increased performance. Until now, however, the grain coarsening inhibition mechanism for effective inhibitors such as V has been elusive, posing an obstacle to material optimization. This study serves to quantify the presence of nanoscale V-W-C over a wide range of V/Co ratios by small-angle neutron scattering (SANS). The experiments help to delineate how additions of V affect the nanostructure during sintering and result in smaller WC grains. In contrast to the common view that grain coarsening inhibition originates from the presence of stable nanoscale (V,W)Cx complexions formed at the WC/Co interfaces, we show that V segregates at the WC/Co interfaces already upon a minor addition of V and brings significant coarsening inhibition. Increasing additions of V result in the formation of (V,W)Cx complexions; and above 0.76 wt% V addition, where the coverage on WC grains is complete, no further reduction in average grain size is observed. Mechanistic modelling of grain coarsening reveals that grain coarsening inhibition is governed by the reduction of interface mobilities and total driving force for coarsening.

Hard metals

Small-angle neutron scattering (SANS)

Computational thermodynamics

Mechanical properties

Grain refining

Författare

Ahmet Bahadir Yildiz

Kungliga Tekniska Högskolan (KTH)

R. Prasath Babu

Kungliga Tekniska Högskolan (KTH)

Manon Bonvalet-Rolland

Kungliga Tekniska Högskolan (KTH)

Sebastian Busch

Helmholtz

V. Ryukhtin

Nuclear Physics Institute

Jonathan Weidow

Chalmers, Fysik, Materialfysik

S. Norgren

Sandvik

P. Hedstrom

Kungliga Tekniska Högskolan (KTH)

Materials and Design

0264-1275 (ISSN)

Vol. 207 109825

Ämneskategorier

Keramteknik

Materialkemi

Metallurgi och metalliska material

DOI

10.1016/j.matdes.2021.109825

Mer information

Senast uppdaterat

2021-07-05