Abstract
Specimens of an AISI4135H steel were traversed across a focused laser beam and superficially alloyed using a co-deposition technique involving B4C powder injection. The metallurgical phases appearing at different depths in the laser surface alloyed steel have been identified using optical microscopy and SEM observations as well as X-ray diffraction analyses and Auger electron spectroscopy. A high hardness in the melted zone was generally obtained. Optimum process parameters including powder feedrate and specimen traverse rate have been determined to avoid porosity or cracks.