碳化钨基硬质合金的制备与力学性能研究

Preparation and mechanical properties of tungsten carbide-based cemented carbides

在碳化钨粉末中加入一定量的钴、碳化钽以及碳化铪,经过混料、球磨、冷压成型和热压烧结等步骤制备出硬质合金试样。利用1 000 N维式显微硬度计、三点弯曲试验、XJJ-5冲击试验机以及扫描电镜分别对试样硬度、抗弯强度、冲击韧性以及试样的微观形貌进行了研究,并对试样力学性能的提高机理进行了探讨。结果表明,碳化铪的加入可有效改善烧结质量,细化晶粒,改善试样力学性能。碳化铪质量分数为2%的试样力学性能最好。

A certain amount of cobalt,tantalum carbide and hafnium carbide powder were added to tungsten carbide powder to prepare a cemented carbide sample through mixing,ball milling,cold forming and hot pressing sintering. The hardness,bending strength,impact toughness,and micro-morphology of the specimens were studied using a 1 000 N dimensional microhardness tester, a three-point bending test, an XJJ-5 impact tester, and a scanning electron microscope,then the mechanism of improving the mechanical properties of the specimen was discussed. The results show that the addition of hafnium carbide can effectively improve the sintering quality,inhibit the growth of tungsten carbide grains and improve the mechanical properties of the samples. The samples with hafnium carbide content of 2% have the best mechanical properties.