Subsurface damage in milling of lightweight open-cell aluminium foams

The present study examined the surface integrity of open cell aluminium foams at full volume using X-ray micro-computed tomography. The structural network was reconstructed in voxel models, for which watershed segmentation and medial axis extraction was utilized to identify interconnected pore (air) and strut (solid) phases. From these models, post-mortem surface integrity characteristics, including pore size, strut bending angle and preferential strut orientation were characterized as a function of controllable parameters of cutting speed, feed rate and depth of cut. Post-mortem characterization of the damage enabled mapping of fundamental failure mechanisms in the mechanics of the subsurface deformation.