What are the effects of rare earths on the properties of nickel base superalloys?
In the electronic theory of studying the effect of rare earth on the performance of nickel base superalloy, it is found that rare earth and impurity sulfur attract each other, which results in the dispersion and fixation of some impurities, and can improve the high-temperature performance of the alloy. Recent studies have found that the addition of carbon can purify the alloy liquid, improve the corrosion resistance of the alloy, and reduce the probability of recrystallization. Micro addition of carbon is also conducive to reducing the content of alloy shrinkage cavity. Liu Lirong et al. found when studying the effect of carbon on the as cast structure of a single crystal nickel base superalloy that, with the increase of carbon content, the initial melting temperature of the alloy gradually decreased, the number and size of eutectic decreased, and the number of carbides gradually increased. The morphology of carbides changed from spotty to a network structure combining spotty and skeleton. The primary dendrite spacing changed greatly, while the secondary dendrite spacing changed little, and the segregation of W and Al elements decreased, The segregation of Ta and Mo elements increases.
