烧结直接淬火对WC－TiC－Co合金WC相微观结构及力学性能的影响

INFLUENCE OF DIRECT QUENCHING OF AS-SINTERED YT14 CEMENTED CARBIDE ON THE MICROSTRUCTURE AND MECHANICAL PROPERTIES OF WCPHASE

本文以ＴＥＭ和ＸＲＤ为主要手段，研究ＷＣ－ＴｉＣ－Ｃｏ硬质合金（ＹＴ１４）在直接淬火后ＷＣ相的微观结构和微观应力，比较了常规烧结态与淬火态试样ＷＣ相之间的差异，探讨了直接淬火对合金力学性能的影响。结果表明，在保持合金其他性能不降低的同时，直接淬火的抗弯强度比常规烧结提高２８％左右。并首次发现，经直接淬火热处理的ＹＴＩ４合会中与Ｃｏ相相邻的ＷＣ晶粒边界出现滑移台阶，这是淬火过程中热应力使ＷＣ晶粒内位错在｛０００１｝密排面聚集，并可能沿｛０００１｝＜１１２０＞易滑移系统强滑移的结果。直接淬火试样的微观应力比重新加热淬火的低。

As-sintered WC-TiC-Co alloy(YT14 ) was subjected to a direct quenching,and the microstructures and micro-stresses of WC phases investigated using TEM and XRD. By comparing the difference in WC phases between quenched and conventional sintered speci-mens,and studying the effect of direct quenching on mechanical properties, slip steps were for the first time discovered on the interfaces between Co phase and WC grains and confirmed by TEM observation, The formation of slip steps can be ascribed to the hot-stresses generat-ed during quenching. The transverse rupture strength of the alloy can be improved withoutdeterioration of its other properties by direct quenching of as-sintered YT14 alloy.