Effect of Collocation Ratio of Coarse and Fine WC on Dual Grain Structure Cemented Carbide

Abstract

This paper adopts area conversion method to measure the WC grain size manually, sets up a Fibonacci Sequence plane segmentation model based on the statistical data obtained, and studies the effect of the ratio of coarse WC grains to fine WC grains on dual grain structure cemented carbide. It is believed that when SWC (fine) / SWC (coarse) ratio is 0.382, theoretically speaking, the arrangement between WC grains is the tightest. Through investigating the effect of WC grain boundary fusion on its stacking density and contiguity, and the effect of the dissolution and precipitation of WC grains on SWC(fine) / SWC(coarse) ratio, and combining Li Guangyu’s random stacking structure of the cemented carbide theory, it expounds the formation mechanism of the dual grain structure cemented carbide—making a proper amount of fine WC grains fill in the gaps between coarse WC grains so as to increase the stacking density and contiguity of WC grains to the maximum degree, and to separate the accumulated Co-phase layer between coarse WC grains, so that the Co layer more evenly distributes among the fine WC grains.