Papers by Keyword: Ti(C,N)

Abstract: Ti(C,N) solid solution were prepared at 1450°C and 1atm nitrogen pressure and the effect of the ways of adding nitrogen on the mechanical properties and microstructures of Ti(C,N)-based cermets were investigated. XRD and FESEM were employed to characterize the as-prepared Ti(C,N)-based cermets. Vickers hardness and fracture toughness were also tested. As a result, The mechanical properties of Ti(C,N)-based cermets prepared by Ti(C,N) solid solution is better than that directly prepared by TiN. The former shows the homogeneous microstructures, the same particle size of hard phases, low porosity, and good sintering character, due to the significant reducing of denitrification when using Ti(C,N) solid solution to introduce nitrogen element. The cross-section SEM images reveal that the dominant fracture behavior of Ti(C,N)-based cermets is transgranular fracture, also including intergranular rupture. The presence of Ni3Ti brittle phase will affect the fracture toughness property of the as-prepared cermets. The more the content of Ni3Ti is, the lower KIC is.

Abstract: Ti(C,N) cermets were prepared by SPS method. The effects of nickel salt coating as well as ball milling times on the microstructure and mechanical properties of the cermets were investigated. SEM images shows that the nickel was coated homogeneously on the surface of Ti(C,N) powders by mixing Ni salt and Ti(C,N) powder. The grains of Ti(C,N)-based cermets became finer with increasing ball milling time. The flexural strength increased when the balling milling was below 48h, and then decreased with increasing of ball milling time, which was due to the decrease of the flake structure in cermets.

Abstract: The effect of WC or NbC addition on various properties of Ti(C0.7N0.3)-Ni cermets was investigated. The microstructure of Ti(C0.7N0.3)-xWC-20Ni showed a typical core/rim structure, irrespective of the WC content, whereas the structure of Ti(C0.7N0.3)-xNbC-20Ni was different and was dependent on the NbC content. The hardness (HV) and the fracture toughness (KIC) had a tendency to increase marginally, while the coercive force (HC) and the magnetic saturation (4πσ) decreased gradually with an increase in WC or NbC content in the systems studied. In addition, increasing WC content in Ti(C0.7N0.3)-xWC-20Ni system, decarburization was retarded, while denitrification was accelerated.

Abstract: Investigation results of the heat treatment effect on the corrosion resistance of the EN AW-AlCu4Mg1 (A) aluminium alloy base composite materials reinforced with the Ti(C,N) particles with varying volume fractions are presented. Examinations were made of the EN AW-Al Cu4Mg1(A) aluminum alloy, and also of the composite materials with the matrix from this aluminium alloy. It was found out, basing on own research, that corrosion wear after the corrosion tests of the composite materials with the addition of 5% of the Ti(C,N) particles is smaller compared to the pure aluminium alloy. Precipitation hardening causes improvement of the corrosion resistance of the investigated composite materials and - like in the state before the heat treatment, materials with 5% portion of the Ti(C,N) reinforcement ratio are characteristic of more advantageous features compared to the material without the reinforcement.

Abstract: Investigations of composite materials based on EN AW-Al Cu4Mg1(A) aluminum alloy reinforced with the Ti(C,N) particles with various weight ratios of 5, 10, and 15% are presented. Powders of the starting materials were mixed in the laboratory vibratory ball mill to acquire the uniform distribution of reinforcement particles in the matrix material. The components were initially compacted at cold state in a die with the diameter of ∅ 26 mm in the laboratory vertical unidirectional press – with a capacity of 350 kN. The obtained P/M compacts were heated to a temperature of 480÷500°C and finally extruded – with the extrusion pressure of 500 kN. Bars with a diameter of 8 mm were obtained as the end product. Based on the microstructural examinations of the obtained composite materials, the uniform distribution of the reinforcing particles in the aluminum matrix was revealed. Hardness tests, tensile tests and the ultimate compressive strength tests made it possible demonstrate that all these properties change along with the reinforcing particles concentration change.

Abstract: In this study, the development of a functionally graded material (FGM) with hard outer surfaces and a tougher inner core was envisaged. The applicability of electrophoretic deposition (EPD) for the processing of FGM materials by continuously changing the suspension composition is shown. Optimisation of the colloidal processing technique was combined with hot pressing experiments on homogeneous composites in the Al2O3-ZrO2-Ti(C,N) system in order to create a very hard functionally graded material with beneficial residual stresses. Finally, the residual stress distribution was briefly discussed using an existing analytical model.