Effects of metal binder on the microstructure and mechanical properties of Al2O3-based micro-nanocomposite ceramic tool material

Xiu-Ying Ni,Zuo-Li Li,Jia-Lin Sun,Feng Gong,Jun Zhao

doi:10.1007/s12613-017-1466-6

Xiu-Ying Ni, Zuo-Li Li + Show 3 more

Open Access

https://doi.org/10.1007/s12613-017-1466-6

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Abstract

The Al2O3−(W,Ti)C composites with Ni and Mo additions varying from 0vol% to 12vol% were prepared via hot pressing sintering under 30 MPa. The microstructure was investigated via X-ray diffraction (XRD) and scanning electron microscopy (SEM) equipped with energy dispersive spectrometry (EDS). Mechanical properties such as flexural strength, fracture toughness, and Vickers hardness were also measured. Results show that the main phases A12O3 and (W,Ti)C were detected by XRD. Compound MoNi also existed in sintered nanocomposites. The fracture modes of the nanocomposites were both intergranular and transgranular fractures. The plastic deformation of metal particles and crack bridging were the main toughening mechanisms. The maximum flexural strength and fracture toughness were obtained for 9vol% and 12vol% additions of Ni and Mo, respectively. The hardness of the composites reduced gradually with increasing content of metals Ni and Mo.

Highlights

Ceramic materials have unique mechanical and chemical properties, such as high wear resistance and high hardness, especially at high temperature [1]
Ceramic-metal nanocomposites that exhibit improved flexural strength and fracture toughness may be developed by combining the “nanocomposite effect” with the ductility of the metals
In high-temperature sintering, metal phases are distributed at grain boundaries or triple junctions in the form of liquid state, which is conducive to strengthen grain boundaries [12]

Summary

Introduction

Ceramic materials have unique mechanical and chemical properties, such as high wear resistance and high hardness, especially at high temperature [1]. Their low fracture toughness limits their potential applications. The particle location is a key microstructural parameter to improve the fracture strengths of Ni-reinforced alumina composite. Adding Ni and Mo into Al2O3−(W,Ti)C composite is expected to generate a material with high strength and toughness to improve the impact resistance of cutting tool materials. The influences of varying Ni and Mo contents on the microstructure and mechanical properties of Al2O3−(W,Ti)C−Ni−Mo composites were discussed

Preparation of materials

Specimen processing

Effect of Ni and Mo contents on phase composition

Effect of Ni and Mo contents on microstructure

Effect of Ni and Mo contents on mechanical properties

Conclusions