In impact welding, extremely high plastic strain regions develop. Thus, traditional finite element analysis methods are not able to accurately simulate the process due to excessive element distortion near the contact region. Despite the great successes in developing hybrid and adaptive remeshing techniques, mesh-based numerical methods suffer from difficulties in some aspects which limit their applications in high-strain-rate problems. Recently, with the progress in computational capabilities, the next generation of computational methods, so called meshfree methods, have received significant attention. Among all meshfree methods, smoothed particle hydrodynamics (SPH) has received major consideration. In this study, the high-speed impacts between AM-Steel/AM-Steel, Copper/Copper, and Al/Steel were simulated. Then, to study the effects of coating and diffused materials on weldability, different SPH platforms were developed. To experimentally validate the numerical efforts, vaporizing foil actuator welding (VFAW) was conducted. Good agreement between the simulations and experimental results provided confidence in the computational modeling.