Plastic Deformation of Fine-Grained Al–Cu–Fe–(B) IcosahedralPoly-Quasicrystals at Elevated Temperature

Abstract

Fine-grained Al–Cu–Fe–(B) icosahedral poly-quasicrystals (IQCs) asthe main materials and fine-grained Al–Pd–Mn IQCs as the supplements,both prepared by powder metallurgy, are uniaxially deformed at varioustemperatures and strain rates. The systematic study shows thedependences of curves of the true stress versus true strain on severalparameters, such as temperature, strain rate and grain size. ForAl–Cu–Fe IQCs with grain sizes of about 10–30 μm, QC-specificintra-granular softening drop appears in the deformation curves atlower temperatures and/or faster strain rates, but disappears in thosecurves at higher temperatures and/or slower strain rates, whichsuggests that the inter-granular effects such as grain-boundary slidingshould be taken into account to interpret the continuous hardening,similarly to conventional poly-crystals. For Al–Cu–Fe-B IQCs withsmaller grain sizes of about 1 μm and fine-grained Al–Pd–Mn IQCs withgrain sizes of about 10 μm, QC-specific intra-granular softening dropis absent for all the deformation curves at the possible lowesttemperature and fastest strain rate. This implies that the smaller thegrain size, the more the inter-granular contribution. At the same time,due to the rapid recovery caused by intense diffusion in small-sizedgrains, the intra-granular quasicrystal lattice reorders rapidly fromdisordering, which also inhibits the intra-granular softening drop tosome extent.