The origin of the martensitic transition in the magnetic shape memory alloy Ni-Mn-Ga has been widely discussed. While several studies suggest it is electronically driven, the adaptive martensite model reproduced the peculiar nonharmonic lattice modulation. We used femtosecond spectroscopy to probe the temperature and doping dependence of collective modes, and scanning tunneling microscopy revea...

This work is to the best of my knowledge original, except where acknowledgements and references are made to previous work. Neither this, nor any substantially similar dissertation has been or is being submitted for any other degree, diploma or other qualification at any other university. This dissertation does not exceed 60,000 words in length. Abstract iii DFT Pak, Jun Hak 20080959 Coalesced s...

BACKGROUND To investigate the Cochleo-vestibular clinical and audiometric findings in Multi and Extreme Drug Resistance(MDR and XDR) tuberculosis(TB) patients on treatment and make recommendations. METHODS A cross-sectional study of adult MDR and XDR-TB patients was conducted in a general hospital in Cape-Town-South-Africa. Ethical approval was secured and all consenting patients administered...

Martensitic transformation associated with a tensile deformation of CuAlMn single crystals in [loo] direction was studied using in-situ transmission electron microscopy. Stress/strain curves obtained during pseudoelastic deformation of microscopic samples were slightly different fiom bulk ones due to martensite formation in the stage of stress increase and a permanent deformation during the fir...

in this study, the effects of nitrogen addition on the production of ultrafine/nano grained aisi 201l stainlesssteel by advanced thermo-mechanical process were investigated. cast samples were first homogenized at 1200 °c for 4 h, hot-rolled at 1100 °c and finally, solution-annealed at 1150 °c for 2.5 h. unidirectional and cross multipass cold rolling at 25 °c was carried out to 90% reduction in...

the composition of essential oil isolated from achillea eriophora, achillea millefolium, achillea biebersteinii and achillea tenuifolia growing wild in the south west of iran, was analyzed.  a. eriophora, a. millefolium and a. tenuifolia essential oils were characterized by sabinene, 1, 8-cineole, terpinene-4-ol, ά –bisabolol, p-cymene, β-pinene and α-pinene. the a. biebersteinii essential oil ...

this paper provides an overview on obtaining low-carbon ultra-fine grained dual-phase steels through rapid intercritical annealing of cold-rolled sheet as improved materials for automotive applications. a laboratory processing route was designed that involves cold-rolling of a tempered martensite structure followed by a second tempering step to produce a fine grained aggregate of ferrite and ca...

A workshop has explored interactions of materials science, applied mechanics, physics and mathematics in understanding fundamentals of martensitic transformations. System theory offers a framework for addressing realistic complexity. Theory of invariant-plane kinematics has been extended to multivariant plate groups and hierarchical structures. Electronic total energy calculations explore the o...

Methods for the dilatometric determination of the martensite start temperature of steels are discussed, with emphasis on noise in the experimental data. The methods are tested on a new set of experiments using a specially prepared steel. Relying on the first detection of expansion due to transformation is fraught with difficulties. Instead, an offset method is proposed which should enable indep...

Based on the results that the magnitude of the stabilization of retained austenite increases with increasing the amount of martensite transformed, it has been assumed that the martensitic transformation is accompanied with an increase in internal resisting stress which subsequently results in the stabilization of retained austenite. By simplifying this internal resisting stress to be a type of ...