Nanomechanical properties of Mg–Al intermetallic compounds produced by packed powder diffusion coating (PPDC) on the surface of AZ91E

A packed powder diffusion coating (PPDC) treatment produced two intermetallic layers on the surface of the commercial magnesium alloy AZ91E. The beta-phase (Mg17Al12) was immediately on top of the AZ91E, on top of which was the tau-phase (Mg-32(Al,Zn)(49)). Nanoindentation showed that the elastic modulus and hardness of each of the intermetallic compounds was significantly greater than that of the AZ91E substrate. Staircase displacement bursts occurred during nanoindentation of the intermetallic compounds, attributed to the combination of incipient plasticity at low loads, and the development of dislocation networks due to dislocation pile ups around the indentation at higher loads. Crystallographic analysis of beta phase orientations using EBSD showed that the nanomechanical properties of the intermetallic compound produced through PPDC treatment were isotropic. (C) 2013 Elsevier B.V. All rights reserved

Earth abundant, non-toxic, 3D printed Cu2−xS with high thermoelectric figure of merit

Dataset for: Earth Abundant, Non-Toxic, 3D Printed Cu2-xS with High Thermoelectric Figure of Merit The toxicity, earth abundance and manufacturing costs of thermoelectric materials are three leading reasons why thermoelectric generators are not used in wide scale applications. This is the first ever paper to tackle all three of these problems at once. A pseudo-3D printing technique is combined with Cu2-xS based inks to yield bulk samples capable of being using in traditional architecture thermoelectric generators. These bulk samples are characterized over a wide temperature range in XPS, which reveals a curing temperature of 550 K yields pure Cu2-xS samples. The thermoelectric properties of these samples are tested over a wide temperature range, with a peak ZT of 0.63 ± 0.09 being recorded at 966 K.Data published in the Journal of Materials Chemistry A DOI of publication: 10.1039/C9TA10064

A pragmatic continuum level model for the prediction of the onset of keyholing in laser powder bed fusion

Laser powder bed fusion (L-PBF) is a complex process involving a range of multi-scale and multi-physical phenomena. There has been much research involved in creating numerical models of this process using both high and low fidelity modelling approaches where various approximations are made. Generally, to model single lines within the process to predict melt pool geometry and mode, high fidelity computationally intensive models are used which, for industrial purposes, may not be suitable. The model proposed in this work uses a pragmatic continuum level methodology with an ablation limiting approach at the mesoscale coupled with measured thermophysical properties. This model is compared with single line experiments over a range of input parameters using a modulated yttrium fibre laser with varying power and line speeds for a fixed powder layer thickness. A good trend is found between the predicted and measured width and depth of the tracks for 316L stainless steel where the transition into keyhole mode welds was predicted within 13% of experiments. The work presented highlights that pragmatic reduced physics-based modelling can accurately capture weld geometry which could be applied to more practical based uses in the L-PBF process

Ueber die Reflexionsverminderung an Grenzflächen zwischen durchsichtigen Körpern

[no abstract available