The plane-strain bulge test is used to investigate the mechanical behavior of freestanding electroplated Cu thin films as a function of film thickness and microstructure. The stiffness of the films increases slightly with decreasing film thickness because of changes in the crystallographic texture and the elastic anisotropy of Cu. Experimental stiffness values agree well with values derived fro...

Understanding the grain size-dependent failure behavior of polycrystalline graphene is important for its applications both structurally and functionally. Here we perform molecular dynamics simulations to study the failure behavior of polycrystalline graphene by varying both grain size and distribution. We show that polycrystalline graphene fails in a brittle mode and grain boundary junctions se...

This study investigated the grain size dependence of mechanical properties and deformation mechanisms of microcrystalline (mc) and nanocrystalline (nc: grain size below 100 nm) Mg-5wt% Al alloys. The Hall-Petch relationship was investigated by both instrumented indentation tests and compression tests. The test results from the indentation tests and compression tests match well with each other. ...

An ultra-fine-grained AISI 301LN austenitic stainless steel has been achieved by heavy cold rolling, to induce the formation of martensite, and subsequent annealing at 800 C, 900 C, and 1000 C, from 1 to 100 seconds. The microstructural evolution was analyzed using transmission electron microscopy and the yield strength determined by tension testing. Ultra-fine austenite grains, as small as ~0....

We study the combined effects of grain size and texture on the strength of nanocrystalline copper (Cu) and nickel (Ni) using a crystal-plasticity based mechanics model. Within the model, slip occurs in discrete slip events exclusively by individual dislocations emitted statistically from the grain boundaries. We show that a Hall-Petch relationship emerges in both initially texture and non-textu...

Nanocrystalline TiN has been imbedded in amorphous silicon nitride matrix to form a super hard nanocomposite thin film (ncTiNya-SiN ) via magnetron sputtering. Adjusting Ti and Si N target power ratio altered film composition, size, amount and x 3 4 distribution of the nc-TiN phase. At a Ti target power density of 5.5 W cm , the Ti to Si N target power ratio should be greater y2 3 4 than unity ...

An analytical solution shows that a competition between bond order loss and the associated bond strength gain of the lower coordinated atoms near the edge of a surface dictates the mechanics of the surface and, hence, a nanosolid. Bond order loss lowers the activation energy for atomic dislocation, whereas bond strength gain enhances the energy density or mechanical strength in the region near ...

This paper analyses slip transfer at the boundary of nanoscaled growth twins in face-centred cubic (f.c.c.) metals for strengthening mechanism. The required stress for slip transfer, i.e. inter-twin flow stress, is obtained in a simple expression in terms of stacking fault energy and/or twin boundary (TB) energy, constriction energy and activation volume. For nanotwinned Al, Cu and Ni, inter-tw...