Metal matrix composites (MMCs), as advanced substitutes of monolithic metallic materials, are currently getting an increasing trend of research focus as well as industrial applications for demanding applications such as aerospace, nuclear and automotive because of their enhanced mechanical properties and relative lightweight. Nevertheless, machining of MMC materials remains a challenging task as a result of their structural heterogeneity which leads to deterioration of the machined surface integrity and rapid tool wear. While prior review papers have concentrated on the other machining aspects (e.g. process modelling and tool wear) of MMCs, none of them has addressed the subject of reviewing workpiece surface integrity aspects in details. This paper presents a detailed literature survey on the conventional and nonconventional machining of metal matrix composites with the primary focus on the aspects related to workpiece surface integrity. The contribution of material mechanical and microstructural properties as well as the material removal mechanism upon the quality of workpiece surfaces/subsurface are discussed along with their influences on the fatigue performance of machined part.

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The machining of low-rigidity components (e.g. thin-walled) with compliant tools presents accuracy challenges as both sides in contact are being deformed. The controlling method presented in this paper enables, for the first time, to obtain the desired and uniform material removal rate by controlling the nominal tool offset when two bodies (workpiece and tool) are compliant in grinding. A contact deformation model is proposed to predict the relation between the nominal and actual tool offsets. The function of nominal tool offsets and material removal rates is obtained based on the calibration tests. Spot grinding tests have been performed for the validation of the calculated material removal rates, normal grinding forces and spot sizes, presenting position-dependent characteristics. The controlling method has been tested for the case of continuous grinding the whole area of a circular aluminium thin wall. The surfaces ground under the time-variant tool offsets (proposed approach) reach the desired removal depth with an average error of ≤10% and achieve 11.2μm~24.2μm (P-V) accuracy in the elastic domain, compared with the error of 76.8%~113.7% and accuracy of 42.6μm~50.1μm (P-V) in the circumstance of constant tool offsets (conventional approach).

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