Wear mechanism of iron-base diamond-impregnated tool composites

The main objective of the present work was to determine the effect of abrasion induced martensitic transformation occurring in the matrix of diamond-impregnated tool composites on their wear behaviour under quasi-industrial conditions. Various iron-base and cobalt-base powder mixtures were consolidated to a virtually pore-free condition by hot pressing at 850-900 °C. The specimens were subsequently checked for density and tested for resistance to both 3-body and 2-body abrasion. A series of diamond-impregnated specimens (segments) was also produced and tested for wear rate on abrasive sandstone using a special testing rig. The statistical analysis of wear data showed increased resistance to abrasion of alloys containing unstable austenite which could transform to hard martensite under tribological straining. The wear rate of diamond-impregnated composites was mainly affected by the diamond concentration, whereas statistically significant contribution of the matrix resistance to 3-body abrasion to the wear rate of the diamond containing material was exclusively found in iron-base composites containing austenite.