The present disclosure provides assemblies, systems and methods for a single-step process for selective heat treatment of metals. More particularly, the present disclosure provides assemblies, systems and methods for a single-step process for selective heat treatment of metals using multiple heating sources. A hybrid modeling-test approach can be used in the design process to improve or optimize the process parameters to achieve location specific and improved/optimal microstructure and residual stress to enhance the part performance. It is also noted that performing the selective heat treatment in a single step can reduce the cycle time significantly. Moreover, large thermal gradients can be avoided in the part as different volumes of the part are heated to their desired temperature simultaneously.