烧结温度对Ti(C,N)基金属陶瓷组织及力学性能的影响

Influence of sintering temperature on microstructure and mechanical properties of Ti(C,N)-based cermets

采用真空烧结制备了Ti(C,N)-Mo-Ni金属陶瓷,利用扫描电镜(SEM)、能谱仪(EDS)和维氏硬度计研究了烧结温度对Ti(C,N)基金属陶瓷显微组织及力学性能的影响。结果表明:随着烧结温度的提高,粘结相逐渐从块状向网状转变,当烧结温度达到1450℃时,网状粘结相基本形成。1450℃是敏感烧结温度,在此温度,硬质相颗粒开始发生异常长大,且存在尖角硬质相颗粒,尖角的硬质相颗粒易发生穿晶断裂,降低材料的断裂韧性。当烧结温度高于1450℃,硬质相颗粒尺寸逐渐趋于均匀,硬质相颗粒尖角钝化。在1510℃烧结的样品具有较好的显微组织和力学性能,维氏硬度达到1700 HV30,断裂韧性KIC达到8.56 MPa·m^(1/2)。

Ti（C,N）-Mo-Ni cermets were produced by vacuum sintering, and the effects of sintering temperature on its microstructure and mechanical properties were investigated by means of SEM, EDS analysis and hardness test. The results show that the hinder phase gradually transforms from blocks to net-like grains, and starts to appear a homogenous net-like microstructure at 1450 ℃. However, abnormal growth and sharp-angled shape formation of the hard phase particles appear at 1450 ℃, which is a sensitive sintering temperature, and this induces transcrystalline fracture and reduces fracture toughness of the Ti （C, N ）-Mo-Ni cermet. When the temperature exceeds 1450 ℃ , particle size tends to he uniform and sharp angles become blunt for those hard phase. Samples sintered at 1510 ℃ have improved microstructure and mechanical properties, Ti （C, N）-Mo-Ni eermets with Vieker hardness of 1700 HV30 and fracture toughness of 8.56 MPa. m1/2 are obtained.