添加Al_2O_3对粗晶WC-10%Co硬质合金力学性能和显微结构的影响  

Effect of Al_2O_3 Addition on Mechanical Properties and Microstructure of Coarse-grained WC-10%Co Cemented Carbide

作　　者：黄奔[1] 伏坤 周建华[1,2] 李晓峰[1] 

机构地区：[1]中南大学粉末冶金国家重点实验室,湖南长沙410083 [2]长沙中南凯大粉末冶金有限公司,湖南长沙410083

出　　处：《硬质合金》2015年第5期311-316,共6页Cemented Carbides

摘　　要：以超粗碳化钨粉和球形钴粉为原料,通过在粗晶WC-10%Co基体中加入细微Al2O3颗粒,通过低压烧结制备粗晶硬质合金。采用金相显微镜、扫描电子显微镜观察合金微观形貌,测定抗弯强度、冲击韧性、硬度等力学性能。结果表明:添加一定含量的Al2O3可以使硬质合金的晶粒细化,晶粒形貌趋向球化而且分布均匀,因为球化WC晶粒和较大的Co相平均自由程的存在使得裂纹产生偏转、分叉和不连续现象,从而提高硬质合金的抗弯强度,冲击韧性和耐磨性。添加是质量分数0.4%的Al2O3使合金的抗弯强度从2 492 MPa提升到2 832 MPa,冲击韧性从6.18 J/cm2提升到7.52 J/cm2。Using extra coarse WC and spherical cobalt powders as starting materials, coarse-grained cemented carbide was prepared by adding subtle Al2O3 particles into the coarse-grained WC-10%Co through low pressure sintering. Microstructures of the coarse-grained cemented carbide were observed by using SEM and metallographic microscope. Mechanical properties such as flexural strength, impact toughness and hardness were measured. The experimental results show that adding Al2O3 can make carbide grain refined, and make the grain morphology spheroidized. The extra coarse rounded WC grains and thick cobalt interlayers lead to the appearance of bifurcating, diverging and discontinuous cracks, and contribute to improve the flexural strength, impact toughness and wear resistance of cemented carbide. Adding 0.4% Al2O3（mass fraction） can improve the flexural strength of the alloy from 2 492 MPa to 2 832 MPa, and enhance the impact toughness from 6.18 J/cm2 to 7.52 J/cm2.

关 键 词：粗晶 硬质合金 AL2O3 力学性能 显微结构 球化晶粒 

分 类 号：TG135.5[一般工业技术—材料科学与工程]