Influence of Alloy Composition on the Tribomechanical Properties of 50% Blend of CoCrWMoCFeNiSiMn (Stellite 1) and CoCrMoCFeNiSiMn (Stellite 21) Alloys

This paper aims to investigate the structure–property relationship of the blend of two different carbide-type wear resistance Stellite^® alloys, i.e., high-carbon and high-tungsten CoCrWMoCFeNiSiMn (Stellite 1) alloy and high-molybdenum CoCrMoCFeNiSiMn (Stellite 21) alloy. Blended alloys can be tailored to specific tribomechanical properties that cannot be achieved using standard pre-alloyed powders. Gas-atomized powders were HIPed (hot isostatically pressed) in an argon environment for 4 h at a temperature and pressure of 1200 °C and 100 MPa, respectively. The microstructure of the alloys was investigated using X-ray diffraction (XRD) and scanning electron microscopy (SEM). Micro-hardness, macro-hardness (HV), tensile and Charpy impact tests were performed to characterize the mechanical properties. Wear properties were investigated using dry sand rubber wheel (DSRW), self-mated pin-on-disk (PoD) and ball-on-flat (BoF) tests. Relationships between the chemical composition of the alloys and total carbide fraction (TCF), hardness, yield strength and Charpy impact energy (Ec) were investigated. Structure–property relationships are developed between the wear rate and chemical composition via mechanical properties. Wear mechanisms are discussed based on phase composition and alloy microstructure. The wear performance was more dominated by relationship TCF×HVEc. Mathematical relationships of wear rate are developed which can be applied to both CoCrW and CoCrWMo alloy blends.