Papers by Keyword: Ti(C, N)-Based Cermets

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Authors: Bin Zhan, Ning Liu, Wei Xu, Jin Gang Shi
Abstract: Four Ti(C, N)-based cermets was fabricated from different size of ceramic powder by the conventional powder metallurgy technique. Microstructure, fracture surfaces and crack propagation path of samples were observed by SEM, and mechanical properties such as transverse rupture strength, hardness and fracture toughness were measured. Results show that with the refinement of the raw TiC/TiN powders, the black cores and ceramic grains tend to be finer, the gains with white core-grey rim structure obviously increase, and the microstructure of cermet becomes inhomogeneous. The cermets fabricated from fine powders possess higher porosities. Compared with the cermets made from micron ceramic powders, the cermets fabricated from ceramic powders containing nano powder possess higher transverse rupture strength and lower fracture toughness. When the cermet is fabricated from micron TiC/nano TiN powders, its combination property is the best.
265
Authors: Peng Wu, Shao Cun Liu, Xiu Rong Jiang
Abstract: The microstructures of the prepared Ti(C, N)-based cermets with various ratios of Co to Ni+Co were studied using X-ray diffractometry (XRD) and scanning electron microscopy (SEM). Mechanical properties such as transverse rupture strength (TRS), fracture toughness (K1C) and hardness (HRA) were also measured. The results showed that when Ni was partly replaced by Co, the core size of hard particle and the thickness of rim phase changed. With the increasing of the ratio of Co to Ni+Co, the porosity of the cermets increased gradually, the fracture toughness of the cermets decreased gradually, the transverse rupture strength increased firstly and then decreased, the hardness changed slightly。When the ratio of Co to Ni+Co was 0.2, the cermets had better transverse rupture strength (TRS), which was characterized by fine grains and the moderate thickness of rim phase in the binder.
292
Authors: Hai Yan Lei, Ping Feng, Xiao Ming Zhang, Teng Biao Zheng
Abstract: The effect of titanium nitride addition on the microstructure, porosity and mechanical properties of Ti(C, N)-based cermets were investigated in this work. Results show that cermets have typical core-rim microstructure, the grain size of hard phase refines and the porosity increases with the addition of titanium nitride content. The transverse rupture strength reaches maximum at about 15wt.% titanium nitride. The hardness declines with the incremental titanium nitride content.
536
Authors: Pei Zhang, Wan Chang Sun, Qing Hao Yang, Pan Li, Xiao Lin She
Abstract: Ti(C,N)-based cermets were prepared by pressureless sintering using micron-sized TiC and TiN powders as main starting materials and Ni and Co as metal binders. The fracture micrographs of Ti(C,N)-based cermets were observed by SEM. The effects of metal binder phase content on porosity and mechanical properties of Ti(C,N)-based cermets were investigated. The results show that when sintering at 1450 °C for 50min, typical core/rim microstructure is observed in the cermets, which is compact and distributed homogeneously, the density and relative density are 5.9 g/cm3 and 95.6%, respectively. Intergranular fracture is the main crack propagation mode, with a few of the transgranular fracture, and there are more dimples and tearing ridges in the fracture surface. Using the same sintering process, Ti(C,N)-based cermets with metal binder content of 10%Ni5%Co has a compact microstructure and fine grains, the metal binder phase is dispersed more evenly, the best vicker hardness, bending strength and fracture toughness of Ti(C,N)-based cermets are 15.8 GPa, 885.5MPa and 9.7 MPa·m1/2, respectively. However, Ti(C,N)-based cermets with Ni replaced of high Co content will generate some brittle intermetallic compound, its toughness is inferior to the metal binder phase, which reduces the strength and toughness of Ti(C,N)-based cermet materials.
438
Authors: Ming Shuang Yan, Wei Hao Xiong, Chou Fan
Abstract: The solvent debinding processes of wax-based binders in powder injection molded Ti(C,N)-based cermets were studied. Effects of debinding temperature, debinding time, sample thickness, solvent types and solvent concentration on binder removal were investigated. Also, the dimension change of samples during the solvent debinding process was studied. It can be found that upwards of 70% paraffin waxes were removed and open pore channels were formed basically when the samples were immersed in heptane for 6 h at 50 °C.
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