Enhanced low-temperature impact toughness of nanostructured Ti

Impact toughness is one of the major mechanical properties for structural materials. It is generally observed that in coarse-grained materials the impact toughness decreases with decreasing testing temperature. Here, we report that the impact toughness of nanostructured Ti processed by severe plastic deformation is enhanced at low temperatures of -70 °C and -196 °C, a unique phenomenon that contradicts the observations in coarse-grained materials. The enhanced impact toughness is attributed to the increased strength and ductility of nanostructured Ti as well as smaller fracture dimples at lower temperatures. This result demonstrates the advantage of using nanostructured Ti in low-temperature applications. © 2006 American Institute of Physics.