Bulk ultra-fine grained materials produced by severe plastic deformation often had low ductility. Here the authors report that simultaneous increases in ductility and strength could be achieved by tailoring the stacking fault energy via alloying. Specifically, ultra-fine grained bronze (Cu-10wt%Zn) with a stacking fault energy of 35mJ/m2 was found to have much higher strength and ductility than ultra-fine grained Cu with a stacking fault energy of 78mJ/m2. Accumulations of both twins and dislocations during tensile testing played a significant role in enhancing the ductility of the ultra-fine grained bronze. This suggested a strategy for designing ultra-fine grained alloys having superior mechanical properties.

Tailoring Stacking Fault Energy for High Ductility and High Strength in Ultrafine Grained Cu and its Alloy. Y.H.Zhao, Y.T.Zhu, X.Z.Liao, Z.Horita, T.G.Langdon: Applied Physics Letters, 2006, 89[12], 121906 (3pp)