Creep and strain burst in indium and aluminium during nanoindentation

Nanoindentation of high-purity vapor deposited lithium films: A mechanistic rationalization of diffusion-mediated flow

“…As reported by Feng and Ngan, 10 this type of behavior has also been observed at high homologous temperatures in indium. Numerous other experimental observations of pop-in events have been reported in the literature as well, but they are generally attributed to the transition from elastic deformation to the onset of dislocation-mediated plasticity.…”

“…After the onset of dislocation motion, the stress exponent increases to ;6. As pointed out by Feng and Ngan, 10 these stress exponents suggest diffusional creep before the onset of dislocation motion and dislocation creep after. A stress exponent near 1 is also reported in low load (1 mN) indentation experiments performed in aluminum by Li and Ngan.…”

“…10 Among the notable outcomes, Asif and Pethica 20 describe how time-dependent deformation observed before the onset of dislocation motion in tungsten (Weihs et al 18 ) and gallium arsenide, both at room temperature, can be attributed to adsorbed surface films and the capillary condensation of water vapor. Capitalizing on the low homologous temperature of indium at room temperature, Feng and Ngan 10 show the stress exponent during creep in indium prior to the onset of dislocation motion is ;1.5. After the onset of dislocation motion, the stress exponent increases to ;6.…”

Nanoindentation of Pb/Sn solder alloys; experimental and finite element simulation results

“…Chudoba and Richter (2001) studied the influence of creep behavior on the determination of hardness and modulus for different combinations of films and substrate materials and for both, Vickers and Berkovich indenters. Feng and Ngan (2001) addressed the problem of ''strain burst'' in an Indium specimen during nanoindentation. Strain burst refers to a sudden displacement excursion following the initial elastic Hertzian contact in a load-controlled machine, or a load drop in a displacement controlled machine.…”

Computer Aided Multi-scale Design of SiC-Si3N4 Nanoceramic Composites for High-Temperature Structural Applications

“…It is believed that when the value of n is 1, creep is controlled by vacancy diffusion as deformation mechanism, [128,129]; when the n value is 2, the creep mechanism the controlled by grain boundary sliding, [130]; when n is 3, diffusion-controlled dislocation motion dominates as deformation mechanism, [131,132]; and when n is 5, it is dislocation climb-controlled creep mechanism, [133]. During indentation creep tests on certain metals, alloys, and ceramics at room temperature, high n values up to hundreds have been observed, [134][135][136][137][138][139][140]. The mechanism behind such high stress exponent values has been attributed to volumetric densification and dislocation pile up.…”