Cr_(3)C_(2)含量对模具用亚微米晶WC-10%Co硬质合金性能的影响

Effects of Cr_(3)C_(2) Content on Properties of Submicron-grained WC-10%Co Cemented Carbide for Mould

本文研究了不同Cr_(3)C_(2)含量对亚微米晶WC-10%Co硬质合金力学性能和磨削性能的影响。结果表明:随着Cr_(3)C_(2)含量的增加,合金硬度、抗弯强度先增大后减小,矫顽磁力增加,断裂韧性及密度降低;当Cr_(3)C_(2)含量达到0.6%(质量分数,下同)时,抗弯强度达到3975 N/mm^(2),硬度HRA达到91.8,密度达到14.38 g/cm^(3),断裂韧性K;达到21.8 MPa·m^(1/2);进一步增加Cr_(3)C_(2)含量(≥1.0%),Cr_(3)C_(2)偏析,合金出现第三相。磨削测试表明:Cr_(3)C_(2)含量在0.6%时,合金刃口平整;Cr_(3)C_(2)含量达到1.0%时合金刃口崩缺比较严重。因而Cr_(3)C_(2)含量在0.6%时,亚微米晶WC-10%Co合金制备的模具具有较好的综合力学性能和磨削加工几何尺寸精度。

The influence of Cr_(3)C_(2) content on mechanical properties and grinding performance of submicron-grained WC-10%Co hard alloys was investigated in the study.Results show that with the increase of Cr_(3)C_(2) content,the hardness and flexural strength of the alloy first increase and then decrease,the coercive force increases,and the fracture toughness and density decrease.When Cr_(3)C_(2) content is 0.6%(mass fraction,the same below),the flexure strength,hardness,density and fracture toughness of the alloy reach 3975 N/mm^(2),91.8 HRA,14.38 g/cm^(3),and 21.8 MPa·m^(1/2),respectively.As Cr_(3)C_(2)content further increased(≥1.0%),Cr_(3)C_(2)segregation occurs,and third phase appeares in the alloy.The grinding test results of WC-10%Co alloys indicate that the alloy edge is smooth with Cr_(3)C_(2)content of 0.6%and the alloy is seriously cracked with Cr_(3)C_(2)content higher than 1.0%.Therefore,the mould prepared by submicron-grained WC-10%Co alloy exhibits better comprehensive mechanical properties and grinding dimension accuracy when the content of Cr_(3)C_(2)is 0.6%.