Achieving fully equiaxed grain structure and ultrahigh density of the high entropy alloy coating via resistance seam processing: experiment and simulation

Abstract

Grain coarsening, high porosity, poor interface bonding and substrate damage are common problems that existed in preparing high-performance coating. Different from the traditional fusion-based coating fabrication methods such as laser cladding, the resistance seam processing method combines the joule heating effect of electrical current with synchronous pressure, which achieves negligible grain growth with fully equiaxed grain structure, ultrahigh density (99.86%), interface metallurgical bonding and friendly to the substrate. A computational fluid dynamics model is established to reveal that the generated high temperature (Exceeding the solidus ~1523 K) is only focused on the tiny interfacial regions (~0.6 µm) between adjacent powders, clearly elucidating the negligible changes in the whole grain size and structure of coating. This study confirms the unique advantages of our fabrication method from both experimental and simulation perspectives, and provides a feasible strategy to prepare high-performance coatings.