Experimental study on the influence of gradient structure design on the thermal response behavior of composite materials

This study investigates how gradient layer thickness affects the thermal response of CuSn10/316L stainless steel composites fabricated by selective laser melting (SLM). Three gradient architectures with varying layer thicknesses were designed and analyzed through both simulation and experiment. Simulations predicted that increasing interfacial layers would enhance thermal barrier performance. However, experimental results showed the opposite trend: samples with thinner layers and lower porosity (10.03%) exhibited poorer thermal barrier properties, while those with thicker layers and higher porosity (15.42%) performed best. This discrepancy reveals that porosity—governed by layer thickness—is the dominant factor controlling thermal behavior, outweighing the effect of interfacial density. Thicker layers promote heat accumulation and gas entrapment, increasing porosity and thermal resistance. The findings establish a clear pathway from gradient layer thickness to porosity evolution to thermal response, providing practical guidance for designing functionally graded materials with tailored thermal barrier performance.