气体雾化快凝W9高速钢粉末的组织特征

研究了颗粒粒度不同的气体雾化W9Mo3Cr4V高速钢粉末的组织、形貌及结构.结果表明:粉末由铁素体和奥氏体基体和分布在周围的MC及M2C型碳化物组成,基体组织为等轴晶及树枝晶,碳化物在空间上呈连续网状或树枝状分布;粉末中相的含量与粉末粒度相关,随高速钢粉末粒度减小,组织中的铁素体和MC型碳化物含量增加,奥氏体和M2C型碳化物含量减少.

Microstructural characteristic of rapidly solidified W9 high speed steel powders

The structure, morphology and constitution of W9Mo3Cr4V high speed steel powder processed by gas atomization have been characterized. Atomized powders with four particle size ranges were examined by means of X- ray diffraction and scanning electron microscopy. The analyses show that the matrix of the powders is a mixture of ferrite and austenite, and the carbides at grain boundaries mainly are MC and M2C. In the range of powder size investigated, the microstructure is found to exhibit a cellular morphology, with carbides existing as continuous network or continuous dendrite. As the particle size decreases, the proportion of ferrite and MC carbides increases, austenite and MC carbides decreases although weight fractions and overall composition of carbides are insensitive to the particle sizes of the powders.