title: Effect of α+β solution treatment and aging on the performance of powder forged Ti-5Al-2.5Fe

authors: Bolzoni, Leandro

subjects: Titanium alloys

abstract: Amongst titanium alloys, the α+β Ti alloys are the ones with the best compromise between strength and fracture toughness. However, the applicability of α+β Ti alloys is limited by their higher cost compared to other structural metals. Reduction of the cost can be obtained using cheaper alloying elements and creative manufacturing processes. This study aims to investigate if α+β Ti alloys can be produced at lower cost using powder forging and to understand the effect that the post-forging α+β solution treatment and aging have on the microstructure and mechanical properties. We demonstrate that the proposed approach is a viable alternative to manufacture α+β Ti alloys and that the chosen forging temperature (i.e. thermal history) is critical for producing high-strength ductile alloys. The microstructural modification induced by the α+β solution treatment and aging generally increases both the strength and the ductility, but the actual improvement is still dictated by the conditions used to thermomechanically deform the α+β Ti alloy.

text: Effect of α+β solution treatment and aging on the performance of powder forged Ti-5Al-2.5Fe Amongst titanium alloys, the α+β Ti alloys are the ones with the best compromise between strength and fracture toughness. However, the applicability of α+β Ti alloys is limited by their higher cost compared to other structural metals. Reduction of the cost can be obtained using cheaper alloying elements and creative manufacturing processes. This study aims to investigate if α+β Ti alloys can be produced at lower cost using powder forging and to understand the effect that the post-forging α+β solution treatment and aging have on the microstructure and mechanical properties. We demonstrate that the proposed approach is a viable alternative to manufacture α+β Ti alloys and that the chosen forging temperature (i.e. thermal history) is critical for producing high-strength ductile alloys. The microstructural modification induced by the α+β solution treatment and aging generally increases both the strength and the ductility, but the actual improvement is still dictated by the conditions used to thermomechanically deform the α+β Ti alloy.

year: 2023-12-31

title: John A. Westgate - Global tephrochronologist, stratigrapher, mentor

authors: Froese, Duane G.

subjects: tephra

abstract: The growth of tephra studies and tephrochronology as a field of research in the last four decades owes an enormous debt to the contributions of John Westgate. John has been one of the clear leaders of this field over this time. Through a career spanning some 40 years, he has been instrumental in the development of research techniques that have led to the global expansion of tephra studies. In particular, he has stressed a multi-proxy approach to tephrochronology, requiring the careful application of glass composition, petrology, and the understanding of field settings and stratigraphy in the development of robust tephrostratigraphic frameworks (Fig. 1 and Fig. 2). In turn, these techniques and records have helped to solve some of the most complex and longstanding problems in the geosciences, geoarchaeology, and other disciplines. John has had a major impact in all countries where he has worked, where he has been a committed researcher, leading and encouraging in his usual fashion and always publishing high-quality and groundbreaking papers that will be used for generations to come. Here we provide a brief summary of John's exceptional career, documenting his very substantial influence on tephra studies worldwide.

text: John A. Westgate - Global tephrochronologist, stratigrapher, mentor The growth of tephra studies and tephrochronology as a field of research in the last four decades owes an enormous debt to the contributions of John Westgate. John has been one of the clear leaders of this field over this time. Through a career spanning some 40 years, he has been instrumental in the development of research techniques that have led to the global expansion of tephra studies. In particular, he has stressed a multi-proxy approach to tephrochronology, requiring the careful application of glass composition, petrology, and the understanding of field settings and stratigraphy in the development of robust tephrostratigraphic frameworks (Fig. 1 and Fig. 2). In turn, these techniques and records have helped to solve some of the most complex and longstanding problems in the geosciences, geoarchaeology, and other disciplines. John has had a major impact in all countries where he has worked, where he has been a committed researcher, leading and encouraging in his usual fashion and always publishing high-quality and groundbreaking papers that will be used for generations to come. Here we provide a brief summary of John's exceptional career, documenting his very substantial influence on tephra studies worldwide.

year: 2008

title: Legal, business and comparative issues in mining and petroleum activity with respect to Māori matters

authors: Barton, Barry

abstract: In this paper I propose to do three things: to identify the very different implications of the different stages of the mining and the oil and gas sequence, to discuss the basics of the Crown Minerals Act and associated legislation, with particular reference to Māori interests, and to touch on a few points of comparison with Canada.

text: Legal, business and comparative issues in mining and petroleum activity with respect to Māori matters In this paper I propose to do three things: to identify the very different implications of the different stages of the mining and the oil and gas sequence, to discuss the basics of the Crown Minerals Act and associated legislation, with particular reference to Māori interests, and to touch on a few points of comparison with Canada.

year: 2014