Laser shock dynamic compaction of tungsten carbide reinforced-aluminum matrix (WCp/Al) composites

Abstract

Laser impact can generate high-strain impact loads. On this basis, a laser impact dynamic compaction (DC) of the tungsten carbide particles (WCp)/Al composite powder with large differences in stiffness and plasticity was performed in this study. Then, the influences of laser energy and WCp content on relative density (actual density/theoretical density), mechanical properties, and microstructure of the pressed billet surface, damage surface, and cross section of the Al matrix composites (WCp/Al) were analyzed. Along with the analysis of the high-strain compaction process, the spread of shock wave process in the compacted billets and the densification behavior of the powder compacts were evaluated via 2D multiparticle finite element method (MPFEM). Results showed that relative density of the compacted billets tended to increase and then decrease with the rise in of WCp content (5%, 10%, 15%, and 20%). In the DC of the composite powder by the laser impact, the pore filling was mainly filled by plastic deformation of the relatively soft Al particles, and the hard WCp did not undergo plastic deformation due to its high strength. A composite powder compact with high relative density was successfully prepared with a WCp content of 10% at 1800 mJ of laser energy. The eventual relative density reached 97.72%, and the overall microhardness increased by approximately 23.25%. The 2D MPFEM simulations could sufficiently predict the dynamic mechanical response in the DC by the laser impact and depict the strain and stress variation patterns at the particle-scale level. Finally, the densification mechanism of the composite powder billets was investigated. The simulation results pertaining to the relationship between the final laser energy and relative density were in significant agreement with the experimental results.