Theoretical study on behaviour of superplastic forming/diffusion bonding of bulk metallic glasses

Based on the behaviour of the superplastic deformation of metallic glasses and Pilling’s model, a diffusion bonding model suitable for metallic glasses is proposed in the present study. In the current model, the diffusion bonding processes consists of two stages: one is the plastic deformation stage and the other is the void shrinkage stage, in which, the atom diffusion and superplastic deformation are responsible for the void shrinkage. Applying this model to the diffusion bonding of a Zr based metallic glass, the predicted bonding time is in good agreement with the experimental result. A map for determining the bonding temperature and time to achieve high quality bonding in a Zr based metallic glass is suggested.

Will these glasses help? Holocaust videotestimony and the transfer of intangible heritage

An analysis of Erica's videotestimony, presented at the Jewish Holocaust Museum and Research Centre in Melbourne, reveals how audio-visual history can act as a medium for the transfer of cultural heritage, despite claims that the trauma of the Holocaust has destroyed the possibility of any meaningful transmissíon. It is argued that the discussion of personal photographs from before and after the Holocaust forms a key component of the videotestimony and constitutes the primary mechanism for intergenerational transfer of Jewish communal heritage, Transfer is further facilitated by the interviewer whose questioning explicitly encourages Erica to reflect on issues of cultural continuity. Significantly, Erica's answers do not always conform to the interviewer's expectations about Jewish communal and religious identification and this can result in tension between the
two. Here too the photographs play an important role in resolving tension between Erica and the interviewer.

Effect of the degree of crystallinity on the electrochemical behavior of Mg65Cu25Y10 and Mg70Zn25Ca5 bulk metallic glasses

The effect of varying the percent crystallinity on the electrochemical behavior of Mg65Cu25Y10 and Mg70Zn25Ca5 bulk metallic glasses was studied. The alloys were heat-treated to achieve desired microstructures ranging from fully amorphous to fully crystalline, providing a systematic basis for subsequent testing. Potentiodynamic experiments in 0.01 M sodium chloride (NaCl) were used, whereby both the amorphous and partially crystallized samples were observed to have more noble corrosion potentials and lower anodic kinetics. However, this was accompanied by more rapid cathodic kinetics relative to their fully crystalline counterparts, meaning that corrosion rates were not significantly lower in the amorphous state. To describe the electrochemical response as a function of the degree of crystallinity, differential scanning calorimetry (DSC), scanning electron microscopy, x-ray diffraction (XRD), and electrical conductivity measurements were undertaken, where it was found that crystallinity alone is not necessarily the controlling factor and microchemistry that evolves upon devitrification, plays a key role in the electrochemical response of these materials.