Effects of V and Co Element Addition on Microstructures and the Mechanical Properties of In Situ Biphasic Hybrid (TiCxNy⁻TiB₂)/Ni Cermets.

Feng Qiu,Yawei Wang,Xiujuan Li,Hongyu Yang,Xiangzheng Duan

doi:10.3390/ma11091750

Feng Qiu, Yawei Wang + Show 3 more

Open Access

https://doi.org/10.3390/ma11091750

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Abstract

In situ micro-(TiCxNy–TiB2)/Ni cermets with different Co and V content (2,5 and 8 wt.%) were successfully fabricated by combustion synthesis and hot press consolidation in Ni–(V/Co)–Ti–B4C–BN systems. The results indicate that as Co content increased from 0 to 8 wt.%, the average sizes of the ceramic particles decreased, when the content of V increased from 0 to 8 wt.%, the size of the ceramic particles first decreased and then increased, and when the V content is 5%, the ceramic particle size is the smallest. The Co element did not participate in the SHS reaction and was a diluent; therefore, when the Co element was added, the combustion temperature continued to decrease. When the V content was no more than 5 wt.%, as the V content increased, the maximum combustion temperature decreased. When the content of V was less than 5 wt.%, the concentration of V was not sufficient to greatly promote the generation of VN. Therefore, V absorbed a large amount of heat during the reaction, resulting in a continuous decrease in the reaction temperature of the reaction system during the reaction. When the content of the added V continued to increase to 8 wt.%, V participated in the reaction, which was exothermic. The results indicate that as Co content increased from 0 to 8 wt.%, the average sizes of the ceramic particles decreased, and the cermets with 5 wt.% Co possessed the best comprehensive properties: the highest hardness (1967 Hv), superior compression strength (3.25 GPa) and higher fracture strain (3.3%). Correspondingly, when the V content was 8 wt.%, the ultimate compressive strength and hardness of the cermets reached 1823 Hv and 3.11 GPa, respectively, 262 Hv and 0.17 GPa higher than those of the unalloyed cermets, respectively. Furthermore, the effects of Co and V on strengthening mechanisms were analyzed.

Highlights

With the development of the aerospace, automotive, exploration and mining industries, higher requirements have been placed on the performance of materials
810, Minneapolis, USA) was applied to the compression with a strain rate measured by the method MN, according to the Archimedes principle. test
When the V and Co contents were continuously increased to 8 wt.%, the ceramics in the cermets in which the Co and V elements were respectively added were similar in size

Summary

Introduction

With the development of the aerospace, automotive, exploration and mining industries, higher requirements have been placed on the performance of materials. Ceramic matrix cermets have a high melting point, stiffness and hardness and are resistant to creep and fatigue [9,10,11,12] This helps to overcome the high density and low temperature resistance of metal materials, and surmounts shortcomings such as the brittleness of structural ceramics [13,14,15]. Study of the effects of the addition of Co and V elements on ceramic particle size, interface binding, element distribution and the mechanical properties of (TiCx Ny +TiB2 )/Ni cermets prepared by in situ reaction of the Ni–Ti–B4 C–BN system [32,33,34,35,36] and analysis of the differences between the influence of the two elements have important value and significance [37,38,39,40]. The effects of Co and V contents on the ceramic particle size, interface binding, element distribution and mechanical properties of (TiCx Ny +TiB2 )/Ni cermets were investigated

Experimental Procedures

3.3.Results

Conclusions