High temperature micropillar compression of Al/SiC nanolaminates

Abstract

The effect of the temperature on the compressive stress-strain behavior of Al/SiC nanoscale multilayers was studied by means of micropillar compression tests at 23 °C and 100 °C. The multilayers (composed of alternating layers of 60 nm in thickness of nanocrystalline A1 and amorphous SiC) showed a very large hardening rate at 23 °C, which led to a flow stress of 3.1 ± 0.2 GPa at 8% strain. However, the flow stress (and the hardening rate) was reduced by 50% at 100 °C. Plastic deformation of the A1 layers was the dominant deformation mechanism at both temperatures, but the A1 layers were extruded out of the micropillar at 100 °C, while A1 plastic flow was constrained by the SiC elastic layers at 23 °C. Finite element simulations of the micropillar compression test indicated the role played by different factors (flow stress of Al, interface strength and friction coefficient) on the mechanical behavior and were able to rationalize the differences in the stress-strain curves between 23 °C and 100 °C.

Comparing small scale plasticity of copper-chromium nanolayered and alloyed thin films at elevated temperatures

“…While several studies have been undertaken to clarify the mechanical behavior of such films at ambient temperature [4][5][6][7][8][9][10][11][12][13][14][15][16], few have investigated the deformation response at elevated temperatures [17][18][19][20][21][22]. These few studies have mostly used the instrumented indentation technique, which despite the ease of testing presents difficulty in direct interpretation of the results due to the complex stress states involved.…”

Decrease of Nano-hardness at Ultra-low Indentation Depths in Copper Single Crystal

“…The mechanical properties of materials at the nanoscale have generated considerable recent research interest [1][2][3][4][5][6][7]. This is due to the fact that some of these properties can change drastically when the dimensions of the sample decrease towards the atomistic scale.…”

Optimum high temperature strength of two-dimensional nanocomposites

“…6,7,10,11 With the recent progress in the development of the high-temperature nanoindentation (HT-Nano) testing technique, [12][13][14][15][16] it is now possible to study the deformation mechanisms within a localized region of the material at high temperatures, and this capability has been shown very valuable to study two-dimensional nanocomposites. 17,18 In this work, we combine the HT-Nano technique and crystal plasticity theory to study the effect of interface structure and layer thickness, L, on the high temperature behavior of a model NMM. We discover that a critical layer thickness, L crit , exists at which the reduction in hardness due to temperature is minimal.…”