摘要
用热等静压设备对Ti(C,N)基金属陶瓷进行了氮化处理,用XRD、SEM/EDX研究了氮化处理温度对Ti(C,N)基金属陶瓷表面显微组织和性能的影响。结果表明,在金属陶瓷表面20μm范围内形成了富含Ti、N的硬化层。表面区较高的N的活度成为合金元素扩散的驱动力。在1150℃氮化处理时,有TiN、WC和Mo2C相在表面区生成。随着氮化处理温度的升高,Mo2C和WC相减少,内环形相和部分外环形相被富N的碳氮化合物所取代,表面区晶粒细化,硬化层逐渐变厚,并在硬化层与基体之间形成了富Ni的过渡层,其有利于提高表面层与基体的结合强度。综合分析认为,在1250℃下氮化处理,可以获得较理想的表面硬化层,其表面显微硬度可达93·8HRA。
Ti（ C ,N）-based cermets were subjected to a heat-treatment by Hot Isostatic Pressing （HIP） in nitrogen. The effect of nitrogen treatment temperatures on microstructures and properties were investigated using X-ray diffraction, scan- ning electron microscopy with energy-dispersive X-ray analysis. It was found that, approximately 20 μm deep, a nitrogenrich and titanium-rich hardened surface zone is introduced by the heat treatment in nitrogen. The high nitrogen activity in the surface zone is the driving force for diffusion of the alloying elements. TiN, WC and Mo2C phases forme in the surface zone of cermets when the nitrogen treatment temperature is 1150 ℃. With the increase of the heat-treated temperature,the contents of WC and Mo2C in the surface zone decrease;the inner rim and outer rim are replaced by nitrogenrich carbonitrides;the microstructures became finer and the thickness of hard surface zone increases gradually. Moreover, the transition band forms between hard surface zone and bulk, which benefits the binding force of them. As a result, the cermet is densified to obtain a surface hardness of 93.8 HRA by heat-treated under 100 MPa in nitrogen at 1250 ℃ for4 h.
出处
《金属热处理》
EI
CAS
CSCD
北大核心
2007年第8期5-8,共4页
Heat Treatment of Metals
基金
国家自然科学基金项目(50074017
50104006)
湖北省耐火材料与高温陶瓷重点实验室开放基金项目(G0507)
华中科技大学塑性成型模拟及模具技术国家重点实验室开放基金项目(05-13)
关键词
TI(C
N)基金属陶瓷
氮化处理温度
热等静压
显微组织
性能
Ti （ C, N） -based cermets
nitrogen treatment temperature
hot isostatic pressing
microstructure
properties
