Mechanical Properties of ECAE Nanocrystalline Copper and Nickel
Bulk nanocrystalline copper and nickel (average grain size ~ 50 nm) with high purity and density were synthesized by equichannel angular extrusion (ECAE). Both nanohardness and microhardness measurements revealed a significant increase in hardness of the bulk sample. The tensile strength of these materials has been found to be 5-6 times higher than conventional forms and our experiments show that Cu is extremely stable up to temperatures of 100 oC and Ni to temperatures of 250 oC. The fracture toughness, measured by the value of JIC for nc-copper and nickel have been found to be 21.66 KJ/m2 and 12.13 KJ/m2, respectively which are high for these strength levels.
M. Gupta and Christina Y.H. Lim
S. Bansal et al., "Mechanical Properties of ECAE Nanocrystalline Copper and Nickel", Journal of Metastable and Nanocrystalline Materials, Vol. 23, pp. 183-186, 2005