Deformation Rate and Temperature Sensitivity in TWIP/TRIP VCrFeCoNi Multi-Principal Element Alloy

High-entropy alloys (HEAs) and medium-entropy alloys (MEAs), also sometimes referred to as multi-principal element alloys (MPEAs), present opportunities to develop new materials with outstanding mechanical properties. Through the careful selection of constituent elements along with optimized thermal processing for proper control of structure, grain size, and deformation mechanisms, many of the newly developed HEA systems exhibit superior strength and ductility levels across a wide range of temperatures, particularly at cryogenic deformation temperatures. Such a remarkable response has been attributed to the hardening capacity of many MPEAs that is achieved through the activation of deformation twinning. More recent compositions have considered phase transforming systems, which have the potential for enhanced strengthening and therefore high strength and ductility levels. However, the strain rate sensitivity of such transforming MPEAs is not well understood and requires further investigation. In this study, the tensile properties of the non-equiatomic V10Cr10Fe45Co30Ni5 MPEA were investigated at different deformation rates and temperatures ranging from 77 K (-196 degrees C) to 573 K (300 degrees C). Depending on the deformation temperature, the considered MPEA exhibits plasticity through either crystallographic slip, deformation twinning, or solid-state phase transformation. At 300 degrees C, only slip-mediated plasticity was observed for all the considered deformation rates. Deformation twinning was detected in samples deformed at room temperature, while face-centered cubic to body-centered cubic phase transformation became more favorable at cryogenic deformation temperatures. The trends are nonlinear with twinning-induced plasticity (TWIP) favored at the intermediate deformation rate, while transformation-induced plasticity (TRIP) was observed, although limited, only at the slowest deformation rate. For all the considered deformation rates at cryogenic deformation temperature, a significant TRIP activity was always detected. The extent of TRIP, however, was dependent on the deformation rate. Increasing the deformation rate is not conducive to TRIP and thus hinders the hardening capacity

Postgraduate pharmacist development- an evaluation of Jordanian pharmacist experiences to inform and shape an evidence-based professional development policy

Building capacity for developing skills as leadership, teamwork, and continuous academic support has become essential for fulfilling a successful pharmacy career. This study aims to assess Jordanian pharmacists’ views on professional development, namely: the continuous education infrastructure, strategies and programs for personal development, leadership skills, incentive schemes, drug information resources and digital services. As well as exploring options for better academic support delivered to pharmacists. To capture participant’s views, an online validated and reliable survey was developed. Non-probability sampling design was used. Participants were qualified pharmacists working at Royal Medical Services (RMS) and Community Pharmacists (CP). Comparison and descriptive statistics were used to report the results. A total of 271 pharmacists participated, 144 from RMS (8% more than the needed sample) and 127 CP (7% more than the needed sample). There was a strong desire amongst both RMS and PC groups for continuous educational training particularly in the following areas, first: Advanced counselling and communication skills (means = 8.99±0.145, CI 95% = 3.70–4.28 and 9.37±0.096, CI 95% = 4.18–4.56). Second: Personal development skills (mean = 8.92±0.142, CI 95% = 3.64–4.20 and 9.02±0.145, CI 95% = 3.73–4.30). Third, Pharmaceutical health promotion (mean = 8.05±0.180, CI 95% = 2.70–3.41 and 8.57±0.159, CI 95% = 3.26–3.89). Only 19.4% and 18.1% of the RMS and CPs respectively reported the presence of a written policy for personal development and leadership in their workplace. There were few incentives for pharmacists to participate in research. Few pharmacists used the available drug information and toxicology centers. The professional and continuous personal development of pharmacists support an evolving healthcare system. This study emphasizes the need for a tailored and documented postgraduate educational strategy, personal development, and leadership skills training in Jordan. Implementing a well-defined scheme of incentives should be encouraged to engage pharmacists in continuous professional development programs and pharmaceutical research. Such strategy and training should enhance both professional and personal performance

A New Shear-Compression Test for Determining the Pressure Influence on the Shear Response of Elastomers

A new shear-compression experiment for investigating the influence of hydrostatic pressure (mean stress) on the large deformation shear response of elastomers is presented. In this new design, a nearly uniform torsional shear strain is superposed on a uniform volumetric compression strain generated by axially deforming specimens confined by a stack of thin steel disks. The new design is effective in applying uniform shear and multiaxial compressive stress on specimens while preventing buckling and barreling during large deformation under high loads. By controlling the applied pressure and shear strain independently of each other, the proposed setup allows for measuring the shear and bulk response of elastomers at arbitrary states within the shear-pressure stress space. Thorough evaluation of the new design is conducted via laboratory measurements and finite element simulations. Practical issues and the need for care in specimen preparation and data reduction are explained and discussed. The main motivation behind developing this setup is to aid in characterizing the influence of pressure or negative dilatation on the constitutive shear response of elastomeric coating materials in general and polyurea in particular. Experimental results obtained with the new design illustrate the significant increase in the shear stiffness of polyurea under moderate to high hydrostatic pressures

On the dynamically stored energy of cold work in pure single crystal and polycrystalline copper

The thermo-mechanical response of single crystal and polycrystalline high purity copper is systematically compared at low and high strain rates. The mechanical response of each type of material is very different in terms of strain hardening, although both are distinctly strain rate sensitive. A simplified interpretation of the Taylor–Quinney coefficient, in which the strain dependence is not considered, shows a clear (almost linear) increase of this factor with the strain rate, while the two types show distinct trends. This factor increases with the strain rate but remains markedly lower than the classical value of 0.9. The stored energy of cold work is found to be relatively independent of the strain rate, with the polycrystal storing more energy than the single crystal. A microstructural study (transmission electron microscopy) of representative specimens of each type at low and high strain rates reveals a basically similar microstructure, despite dissimilar values of energy storage. It is proposed that a higher level of storage of the energy of cold work by polycrystalline copper is due to the presence of grain boundaries in this group