Fatigue and fracture behavior of nanocrystalline copper and nickel

Nanocrystalline (nc) metals are being explored as potential interconnection materials to meet the needs of increased functionality and miniaturization in next generation electronic packages. Fatigue and fracture behavior of these materials is an important aspect in assessing their suitability for this application. This study focuses on evaluating the fracture and fatigue behavior of nc Cu and nc Ni of average grain size of about 50 nm produced by equichannel angular extrusion (ECAE). Fracture toughness tests have been performed using single edge notch bend (SENB) specimens and far-field J values for nc Cu and nc Ni have been found to be 21.66 kJ/m2and 12.13 kJ/m2respectively. The fatigue crack propagation rates also suggest superior fatigue resistance than microcrystalline (mc) Cu and Ni. An initial set of fatigue crack initiation experiments have also been carried out and a significantly higher fatigue resistance is observed compared to their microcrystalline counterparts.

Fatigue and fracture behavior of nanocrystalline copper and nickel Conference Paper