Study on the Effects of Cryogenic Treatment on WC-Co Cemented Carbide at Different Scales Using an Indentation Technique

Cemented carbide (WC-Co) combines high hardness, wear resistance, and toughness, making it ideal for tooling applications. This study investigated cryogenic treatment’s effects on the mechanical properties of samples from various suppliers prepared at different scales. Indentation tests were performed to assess the mechanical properties at the microscale and nanoscale. Overall, the mean microhardness did not show a significant change after cryogenic treatment. Instead, nanoindentation testing was used to identify the improvement after cryogenic treatment. However, considering the mean nanohardness may not adequately capture improvements in the material’s resistance to deformation, the maximum nanoindentation depth and nanohardness were analyzed to elucidate the mechanisms underlying mechanical property improvements in the form of histograms of %frequency along with load–displacement curves. The results showed a decreased frequency of high maximum indentation depths from Co phase improvement. This agreed with an increased frequency of moderate and high nanohardness and a decreased frequency of low nanohardness representing different areas with different phase controls. These results indicate that an alternative interpretation of nanoindentation data, presenting nanohardness and nanoindentation depth in the form of histograms, can provide a more detailed representation of the data distribution.