title: On microstructural evolution and mechanical properties of Ti-5Al-5V-5Mo-3Cr alloy synthesised from elemental powder mixtures

authors: Yang, Fei

subjects: Science & Technology

abstract: In this paper, we explored to prepare a multi-compositional titanium alloy, Ti-5Al-5V-5Mo-3Cr (Ti-5553), by powder compact extrusion from elemental powder mixtures, and investigate the microstructure variation during the synthesising process and after post heat treatments and the changes of mechanical properties. XRD, OM and SEM were used to analyse the phase constitutions and microstructures of the Ti-5553 alloy at different processing conditions, and tensile tests were conducted to examine their mechanical properties. The results showed that a homogeneous Ti-5553 alloy was successfully produced by powder compact extrusion from the powder mixtures, β phase was mainly contained in the hot-pressed and 1200°C-extruded Ti-5553 alloy and had an equiaxed microstructure. Different types of α phase precipitated from the β matrix after heat treatment, and this significantly changed the microstructures and improved the mechanical properties of the extruded Ti-5553 alloy, with yield strength of 1250 MPa and ultimate strength of 1300 MPa for the alloy treated at 675 °C for 2 h, and the ductility of about 6.1% for the alloy treated at 780 °C for 2 h.

text: On microstructural evolution and mechanical properties of Ti-5Al-5V-5Mo-3Cr alloy synthesised from elemental powder mixtures In this paper, we explored to prepare a multi-compositional titanium alloy, Ti-5Al-5V-5Mo-3Cr (Ti-5553), by powder compact extrusion from elemental powder mixtures, and investigate the microstructure variation during the synthesising process and after post heat treatments and the changes of mechanical properties. XRD, OM and SEM were used to analyse the phase constitutions and microstructures of the Ti-5553 alloy at different processing conditions, and tensile tests were conducted to examine their mechanical properties. The results showed that a homogeneous Ti-5553 alloy was successfully produced by powder compact extrusion from the powder mixtures, β phase was mainly contained in the hot-pressed and 1200°C-extruded Ti-5553 alloy and had an equiaxed microstructure. Different types of α phase precipitated from the β matrix after heat treatment, and this significantly changed the microstructures and improved the mechanical properties of the extruded Ti-5553 alloy, with yield strength of 1250 MPa and ultimate strength of 1300 MPa for the alloy treated at 675 °C for 2 h, and the ductility of about 6.1% for the alloy treated at 780 °C for 2 h.

year: 2018

title: Introduction

authors: van Ommen, Clifford

abstract: The concept of the precariat links to situations and experiences of uncertainty, dependency, powerlessness, perilousness and insufficiency. In one sense, precarity refers to the negative consequences for the wellbeing and survival of citizens following the gradual dismantling of the welfare state and union representation; in another related sense, it refers to the changing nature of work that becomes intermittent, insecure and insufficient. Precarity emerges within the global context of a neoliberal economic system that demands greater (job, skill, employment, time) flexibility among individuals so as to improve market competition on a global level.

text: Introduction The concept of the precariat links to situations and experiences of uncertainty, dependency, powerlessness, perilousness and insufficiency. In one sense, precarity refers to the negative consequences for the wellbeing and survival of citizens following the gradual dismantling of the welfare state and union representation; in another related sense, it refers to the changing nature of work that becomes intermittent, insecure and insufficient. Precarity emerges within the global context of a neoliberal economic system that demands greater (job, skill, employment, time) flexibility among individuals so as to improve market competition on a global level.

year: 2017

title: Replacing medical and social models of disability by a communities-based model of equal access for people of differing abilities: A Māori perspective

authors: Hickey, Huhana

subjects: New Zealand

abstract: I argue here that although the social model of disability which currently prevails in New Zealand is preferable in many ways to the earlier medical model, it is nevertheless based on a largely uni-dimensional concept of society and continues an established tradition of negativity, one that is evident in the ongoing use of the word 'disabled' itself by those who subscribe to the social model. I argue here that the social model of disability should be replaced by a communities-based model of equal access for people of differing abilities, one that is, in the New Zealand context, informed by a further developed Māori model of health and wellbeing proposed by Mason Durie, Te Whare Tapa Whā. This mode is designed in such a way as to accommodate difference and diversity. In the discussion of different models, I use the words 'disabled' and 'disability'; in other contexts, I replace 'disabled people' by 'people of differing abilities'.

text: Replacing medical and social models of disability by a communities-based model of equal access for people of differing abilities: A Māori perspective I argue here that although the social model of disability which currently prevails in New Zealand is preferable in many ways to the earlier medical model, it is nevertheless based on a largely uni-dimensional concept of society and continues an established tradition of negativity, one that is evident in the ongoing use of the word 'disabled' itself by those who subscribe to the social model. I argue here that the social model of disability should be replaced by a communities-based model of equal access for people of differing abilities, one that is, in the New Zealand context, informed by a further developed Māori model of health and wellbeing proposed by Mason Durie, Te Whare Tapa Whā. This mode is designed in such a way as to accommodate difference and diversity. In the discussion of different models, I use the words 'disabled' and 'disability'; in other contexts, I replace 'disabled people' by 'people of differing abilities'.

year: 2006-02