Microstructure and Mechanical Properties of TiC0.7N0.3-HfC-WC-Ni-Mo Cermet Tool Materials

Abstract

TiC0.7N0.3-HfC-WC-Ni-Mo cermet tool materials were fabricated by hot pressing technology at 1450 °C. The effects of WC (tungsten carbide) content on the microstructure and mechanical properties of TiC0.7N0.3-HfC-WC-Ni-Mo cermet tool materials were investigated. The results showed that the TiC0.7N0.3-HfC-WC-Ni-Mo cermets were mainly composed of TiC0.7N0.3, Ni, and (Ti, Hf, W, Mo)(C, N); there were three phases: a dark phase, a gray phase, and a light gray phase. The dark phase was the undissolved TiC0.7N0.3, the gray phase was the solid solution (Ti, Hf, W, Mo)(C, N) poor in Hf, W, and Mo, and the light gray phase was the solid solution (Ti, Hf, W, Mo)(C, N) rich in Hf, W, and Mo. The increase of WC content could promote the process of HfC to form a solid solution and the HfC formed a solid solution more easily with WC than with TiCN. The increase of the solid solution made the microstructure more uniform and the mechanical properties better. In addition, the Vickers hardness, flexural strength, and fracture toughness of the TiC0.7N0.3-HfC-WC-Ni-Mo cermet increased with the increase of WC content. When the content of WC was 32 wt %, the cermet obtained the optimal comprehensive mechanical properties in this investigation. The toughening mechanism of TiC0.7N0.3-HfC-WC-Ni-Mo cermet tool materials included solid solution toughening, particle dispersion toughening, crack bridging, and crack deflection.

Influence of WC addition on mechanical properties of (HfNbTaZrTiMo)C‐Co cermet

“…Compared with the samples without WC, the K IC of the samples containing WC is improved to a certain extent. Gao et al 43 . found that since the wettability of Ni with WC was much better than that of Ni with TiCN, the relative density and comprehensive properties of the samples were improved with the increase of WC content.…”

“…42 Compared with the samples without WC, the K IC of the samples containing WC is improved to a certain extent. Gao et al 43 found that since the wettability of Ni with WC was much better than that of Ni with TiCN, the relative density and comprehensive properties of the samples were improved with the increase of WC content. Similarly, the addition of WC also improves the wettability of Co to HEC 6 phase and enhances the intergranular interfacial bonding force, thus improving the mechanical properties of cermet.…”

Cutting performances of TiCN–HfC and TiCN–HfC–WC ceramic tools in dry turning hardened AISI H13

“…Cutting experiments were performed on the i5T5 intelligent lathe under dry cutting condition. TiCN–HfC [7] (TH) and TiCN–HfC–WC [8] (THW) ceramics were obtained through the hot-pressing sintering technology; their mechanical properties and microstructures were showed in Table 1; HV, σ and K IC presented Vickers Hardness, flexural strength and fracture toughness, respectively. TH and THW tools were a cuboid with a size of 12mm × 12mm × 8 mm as shown in Figure 1.…”

“…Usually, the reinforcements such as WC, VC, TaC, NbC and Mo 2 C, and metal phase such as Ni, Co and Mo were employed in TiCN ceramic, which was aimed at improving fracture toughness [4][5][6]. In our previous research, the novel TiCN-HfC [7] and TiCN-HfC-WC [8] ceramics had been fabricated by hot-press sintering technology; they had good fracture toughness, hardness and flexural strength; however, their cutting performances and wear mechanisms have not been investigated.…”

“…In this paper, cutting performances of TiCN–HfC [7] and TiCN–HfC–WC [8] ceramic tools in high-speed turning hardened AISI H13 without coolant would be investigated. Tool life, workpiece surface roughness and tool wear mechanisms would be revealed.…”