Morphological analysis of SSM Al-4.5wt.% Cu measured by the rheocast quality index
Abstract There is a direct relationship between grain size obtained from macrostructure characterisation and the globule size and shape factor, obtained from microstructure characterisation: the smaller the grain size, the smaller the globule size and shape factor. Due to this a rheocast quality index ( RQI = globule size /( grain size × shape factor) ) was used to evaluate the Al–4.5 wt.% Cu alloy produced by strain induced melting activation (SIMA). The structure that presents the smallest grain size, the smallest shape factor, and the most homogeneous and globular size of the primary phase, has the best RQI and consequently the best behaviour in the semi-solid forming. Four different as-cast structures were cold rolled to obtain 20 and 40% deformation and were partially melted at 635 °C at holding times of 5 min. Both, macro- and microstructure were characterised.
Special grain boundaries in rheocast AlMg
Abstract Al10%Mg alloy was stirred in a batch-type apparatus at a low cooling rate (1.5 K min −1 ) for a range of stirring periods and shear rates and was quenched in the semisolid state. The microstructure of alloys so obtained was examined by optical microscopy. Depending on the shear rates and stirring periods, unusual boundaries were observed to have formed in the primary solids. Misorientations measured across these boundaries, using the X-ray microbeam Laue technique, identified them to be “special” boundaries. An attempt was made to explain the origin of these boundaries. Collisions of two previously separate solids followed by sintering and the growth twinning mechanisms are thought to be two possibilities for the formation of such boundaries.
Data Driven Policy: The Case for Certification Research
This article describes the program of research being implemented to investigate the outcomes of certification in the U.S. and Canadian workforce and its relevance to the goal of providing policy makers with pragmatic, action-oriented recommendations. Such recommendations encompass policy issues of workforce production, regulation, distribution, financing, and oversight of credentialing organizations. Few studies exist to substantiate the association between certification credentialing and practice outcomes, thereby leaving policy makers, consumers, and nurses in a vacuum when pushed to protect the public through the credentialing vehicles. The Nursing Credentialing Research Coalition (NCRC) has embarked on a research program that will reveal the relationship between certification and its influence on a nurse’s personal, professional, and practice characteristics as well as those judged by consumers and employers. Selected findings and implications for policy are described. Certified nurses’ reports of early interventions for complications are important quality measures for policy.