The effect of porosity on the mechanical property of metal-bonded diamond grinding wheel fabricated by selective laser melting (SLM)

Abstract

Selective laser melting (SLM) technology is applied to fabricate grinding wheel with high porosity and controllable porous structure. Octahedron cellular structures with porosities ranging from 0.3 to 0.7 and AlSi10Mg/diamond composite are fabricated and investigated in terms of morphological properties and mechanical properties. Characterizations of cellular structure, grain-bond interface and practical porosity are performed. Compression test and three-point bending test are carried out to study the effect of porosity on mechanical property of grinding wheel. The results show that metallurgical bonding forms at the grain-bond interface for the SLM-fabricated composite. The compressive characteristics conform to the classic Gibson-Ashby model for stretch-dominated cellular structure and have positive correlation and linear relationship with relative density. Flexural strength is linear with relative density while flexural modulus is non-linear with relative density. The specimen shape changes from cube to prism, barrel or cuboid during compression test corresponding to three different failure modes. The initial crack always generates in the middle region of specimen and propagates from bottom to top till absolute fracture during three-point bending test. The deformation behavior of SLM-fabricated porous composite resembles to brittle material.