University ’ s repository of research publications and other research outputs The effects of electropulsing on metallic materials Book Chapter
The influence of electropulsing on metallic materials is reviewed, with a focus on phase transformations and grain refinement. While a large and growing body of literature exists on the topic of electropulsing, the mechanisms governing the process are not currently fully understood. Furthermore, the effects of electropulsing on microstructure and mechanical properties are not yet clearly defined. This review seeks to summarise the existing literature in order to highlight and understand research trends across a variety of metals and alloys, and to clarify the state of the art. Research has shown that the electropulsing process is capable of inducing low temperature recrystallisation in metallic materials at an accelerated rate compared to more traditional heat treatment methods. These microstructural changes often alter the mechanical properties of the materials such as ductility, tensile strength and hardness. Crack healing as a result of electropulsing treatment has also been observed in damaged or work hardened materials and pre-deformation of the sample has been shown to enhance the effects of electropulsing.
Electroplastic effect in metals
Abstract : The influence of electric current on the mechanical properties of metals is reviewed. Included are the effects of both low density approx. 1A/sq mm continuous current and high density approx. (1000A/sq mm) current pulses, with special attention given to the latter. The influence of the parameters involved in the thermally-activated overcoming of short-range obstacles to dislocation motion. Considered are: (a) the force drift electrons exert on dislocations held up at obstacles and (b) the influence of drift electrons on the obstacle strength and on the pre-exponential factor. (Author)
Novel polymeric hydrogel composites: Synthesis, physicochemical, mechanical and biocompatible properties
In this research study, novel hydrogel composite films were constructed using different ratios of poly (vinyl alcohol) (PVA)/kappa-carrageenan (KC) (PVA90/KC10%, PVA80/KC20%, PVA70/KC30%, PVA60/KC40%) crosslinked with glutaraldehyde (0.025%) and investigated their physicochemical characteristics such as mechanical, thermal, morphological, swelling behaviour, and cell viability. SEM and FTIR revealed that surface morphology changed to heterogeneous and the presence of molecular interaction among the polymers. PVA90KC10 and PVA60KC40 exhibited smaller and larger pores on surface respectively. The change in the proportion of PVA and KC also triggered the tensile strength (Ts) of the film and the highest Ts observed were 21.60 MPa for PVA60KC40. Moreover, the thermal analysis showed three-phase degradation, and an increase in KC40 concentration results inversely proportional to a decrease in the rate of thermal degradation. Further, swelling and in-vitro biodegradation study confirmed the enhanced perseverance of water uptake for PVA60KC40 (286%) due to pores structure of the hydrogel film and PVA and KC alone degraded faster as compare to other films results suggested higher concentration of PVA90KC10 showed lower degradation rate and highest for PVA60KC40 about 6% and 22% respectively. Further, the cell viability was studied with MTT assay method by using NIH3T3 and HEK-293 cells for biocompatibility study revealed NIH3T3 cells were more biocompatible than HEK-293 and cell viability percent for PVA60KC40 showed the highest cell attachment about 99%. Overall corroborating data obtained from the study attested to the average swelling, appreciable mechanical characters, good interaction between molecules, and cell viability of the constructed PVA/KC hydrogel film, these all characters pave to be used as a potential template for biomedical applications such as tissue engineering and drug delivery.