基于机械合金化法制备(Ti,W)C-Ni金属陶瓷的组织与性能

Microstructure and Mechanical Properties of(Ti,W)C-Ni Cermets Prepared by Mechanical Alloying

以Ti、W、C的元素粉末为原料,通过机械合金化法制备了(Ti,W)C固溶体粉末,结果表明:目标成分为(Ti0.95,W0.05)C、(Ti0.9,W0.1)C和(Ti0.85,W0.15)C的混合粉末经高能球磨后有(Ti,W)C固溶体生成,目标成分为(Ti0.8,W0.2)C的混合粉末经球磨后没有反应发生,X射线衍射图仍然为各组分的单质峰。将经8 h球磨得到的目标成分为(Ti0.95,W0.05)C和(Ti0.9,W0.1)C的固溶体粉末与20wt%的Ni粉进行混和,压制成型后在1 450℃下烧结1 h,得到的金属陶瓷的硬度和抗弯强度分别为88 HRA,1 636 MPa和88.7 HRA,1 693 MPa。两种成分的金属陶瓷的显微组织中均含有"白芯-灰环"结构、"黑芯-灰环"结构以及无芯-环结构的陶瓷晶粒。与钨含量较低的样品相比,钨含量较高的样品的晶粒尺寸以及"黑芯-灰环"结构中黑色芯相的尺寸较小,同时具有无芯结构和"白芯-灰环"结构的晶粒数目较多。

（Ti,W）C solid solution powders were prepared by mechanical alloying from Ti, W, C elemental powders, and the effect of milling time on the mixed powders with different W content was also studied. The results show that （Ti,W）C solid solution powders can be synthesized for powders with the compositions of （Ti0.95,W0.05）C、（Ti0.9,W0.1）C and （Ti0.85,W0.15）C through high-energy milling. No reaction teaks place for powders with the composition of （Ti0.8,W0.2）C, and the X-ray diffraction pattern only contains peaks of each elements. （Ti0.95,W0.05）C and （Ti0.09,W0.1）C solid solution powders obtained by 8 h milling were mixed with 20 wt% Ni and then sintered at 1 450 ℃ for one hour. The hardness and transverse rupture strength of these two cermets are 88 HRA, 1 636 MPa and 88.7 HRA, 1 693 MPa, respectively. SEM results show that there exist ceramic grains with ＂white core-gray rim＂ structure, ＂black core-gray rim＂ structure and coreless structure in the microstructure of both cermets. Comparing to the samples with lower W content, the samples with higher W content has smaller grain size and the size of black core in the ＂black core-gray rim＂ structure is also smaller. The number of grains with coreless structure and ＂white core-gray rim＂ structure in the samples with higher W content is also bigger than that in the samples with lower W content.