工艺条件对原位合成WC/W表面复合材料组织和性能的影响

Effects of Technological Conditions on Microstructure and Properties of In-situ Synthesized WC/W Surface Composites

在通有氢气保护的碳气氛中对烧结态钨制品进行高温处理,使其表面原位合成出一定厚度的碳化钨层,从而制备出WC/W表面复合材料。采用密度和硬度测试、金相组织观察等手段研究了高温处理温度和钨基体密度对原位合成WC/W表面复合材料显微组织和性能的影响,并通过SEM/EDS和XRD等手段分析了碳化钨层的元素组成和相成分。结果表明:高温处理温度对碳化钨层的生长厚度和品质有显著影响,钨基体密度对碳化钨层的生长影响不明显。当高温处理温度低于1 800℃时,碳化钨层厚度较薄,自身强度差,但温度过高会导致碳化钨层缺陷增多。钨基体表面原位合成的碳化钨层为柱状晶组织,相成分单一,与钨基体结合紧密,结合面干净无杂质,能充分发挥两种材料在高温下各自的优异性能。

Tungsten carbide layers with a certain thickness were in-situ synthesized on the surface of sintered tungsten products by high temperature heat treatment in carbon atmosphere protected by hydrogen gas to prepare WC/W surface composites.The effects of heat treatment temperature and tungsten matrix density on microstructure and properties of in-situ synthesized WC/W surface composites were studied by density and hardness test and metallographic microscope.The element composition and phase composition of tungsten carbide layers were analyzed by SEM/EDS and XRD.The results show that high temperature heat treatment temperature has significant influence on the growth thickness and quality of tungsten carbide layer,while tungsten matrix density has no obvious influence on the growth of tungsten carbide layer.When the temperature is lower than 1 800 ℃,the thickness of the tungsten carbide layer is relatively thin and its strength is poor.However,too high temperature will lead to an increase in defects of the tungsten carbide layer.The tungsten carbide layer in-situ synthesized on the surface of tungsten matrix has columnar crystal microstructure and single phase composition,closely combining with tungsten matrix,and the interface is clean and free of impurities.The surface composites can fully exhibit the excellent properties of the two materials at high temperature.