Effects of cubic carbides and La additions on WC grain morphology,hardness and toughness of WC-Co alloys
(1. State Key Laboratory of Powder Metallurgy, Central South University, Changsha 410083, China;
2. Changsha Mining and Metallurgy Research Institute Co., Ltd., Changsha 410012, China)
2. Changsha Mining and Metallurgy Research Institute Co., Ltd., Changsha 410012, China)
Abstract: Effects of Cr3C2, VC and La2O3 additions on the WC grain morphology, hardness and toughness of WC-10Co alloys were investigated. To intensify the grain growth driving force, nano W and nano C, instead of the conventionally used WC, were used as the starting materials. To obtain a three-dimensional WC grain morphology, the natural sinter skins of the alloys were observed directly by scanning electron microscopy. It is shown that the additions have a strong ability in regulating the WC grain morphological and grain size distribution characteristics and the combinations of hardness and toughness. Due to the formation of regular and homogeneous triangular platelet WC grains, WC-10Co-0.6Cr3C2-0.06La2O3 alloy shows an excellent combination of hardness and toughness. The morphological regulation mechanism, the relationship between the WC grain morphology and the properties were discussed.
Key words: cemented carbide; rare earth; grain growth; platelet WC grain; hardness; toughness