WC-10%Co细晶硬质合金晶粒夹粗的模拟研究

Simulation Study on Grain Coarsening of WC-10%Co Fine Grained Cemented Carbide

在细晶硬质合金原料粉末中添加少量4μm和11μm的WC粉末模拟合金中的晶粒一般夹粗和异常长大,研究粗晶WC含量及尺寸对WC-10%Co细晶硬质合金组织与性能的影响。结果表明:添加2%~8%的4μmWC粉末的合金,合金中的粗晶WC零星分布,粗晶尺寸约4~10μm,粗晶面积分数约0.29%~1.42%;添加2%~8%的11μmWC粉末的合金,合金中的夹粗现象非常明显,粗晶WC大于10μm,粗晶面积分数约0.99%~5.03%,呈现较明显的双峰组织。粗晶WC的粒度和含量影响WC-10%Co细晶硬质合金的性能,当参比原料粉末中添加相同规格的WC粉末时,随着添加量的增加,磁力、硬度、横向断裂强度、抗压强度逐渐下降,断裂韧性逐渐增加。添加2%的4μmWC粉末的WC-10%Co细晶合金,粗晶WC尺寸小于10μm且均匀分布,每平方毫米粗晶个数约为438,粗晶面积分数为0.29%,综合性能可达到未含夹粗WC合金的性能。

A small amount of 4μm and 11μm WC powder was added to the raw material powder of fine-grained cemented carbide to simulate the grain coarsening and abnormal growth in the alloy.The effects of the content and size of coarse-grained WC on the microstructure and properties of WC-10%Co fine-grained cemented carbide were studied.The results show that the coarse-grained WC distributes sporadically in the alloy with 2%~8%4μm WC powder,the coarse-grain size is about 4~10μm,and the coarse-grained area fraction is about 0.29%~1.42%.The coarsening phenomenon is very obvious in the alloy with 2%~8%11μm WC powder,the coarse-grained WC is more than 10μm,and the coarse-grained area fraction is about 0.99%~5.03%,showing obvious bimodal structure.The particle size and content of coarse-grained WC affect the properties of WC-10%Co cemented carbide.When the same specification of WC powder is added to the reference raw powder,with the increase of the content of coarse-grained WC powder,the magnetic force,hardness,transverse fracture strength and compressive strength gradually decrease,while the fracture toughness gradually increases.The results show that the WC-10%Co fine grain alloy with 2%4μm WC powder has uniform distribution and the size of coarse-grained WC is less than 10μm.the number of coarse grains is about 438/mm2and the area fraction of coarse grains is 0.29%.The comprehensive properties of the alloy can reach the properties of the alloy without coarse WC.