Chemically architectured alloys: How interphase width influences the strengthening

Abstract

Chemically architectured alloys are a new concept of microstructure in which two phases are separated by a 3D network of fluctuations of composition, which is called interphase, and which induces a strengthening. Chemically architectured alloys were processed by spark plasma sintering of a mixture of pure Ni and CoCrFeMnNi high entropy alloy with varying conditions. They were characterized by scanning electron microscopy coupled with energy dispersive spectroscopy and electron backscattered diffraction, microhardness and compression tests. It was shown that the width of the interphase can be decreased by decreasing the sintering temperature and increasing the applied pressure. The strengthening effect of the interphase increases when its width decreases and its volume fraction increases. The microstructure of the chemically architectured alloys can be finely controlled by the processing parameters which will permit to maximize the strengthening. Chemical architecturation is thus an efficient and tunable strengthening mechanism.