title: Characterisation, Consolidation and Mechanical Properties of TiAl Alloy Produced Using Titanox Powders

authors: Parmar, Bhupinder

subjects: TiAl alloys

abstract: Characterization of the three different as- received TiAl powders, namely Tax1, Tax2 and Tax3 produced by Titanox development Ltd has been done. Predominate TiAl phase was observed in all the three compositions .The powder particles were very fine with average particle size of 12μm, 5μm and 10μm respectively for Tax1, Tax2 and Tax3.Chemical analysis of the powders showed high oxygen content in all the three compositions of the powders .
Bulk samples were produced from Tax1, Tax2 and Tax3 powders by hot isostatic pressing at 1200  C under a pressure of 200Mpa for two hours .The pressurization gas used for the process was argon. The relative density of Tax1, Tax2 and Tax3 HIPped samples was 96%, 86% and 93%and respectively. The characterization of the HIPped samples showed that the predominate phase was γ-TiAl phase in all the three HIPped samples .A small fractions of Ti3Al and TiAl3 was also observed in tax1 and Tax3 HIPped material. Also some of the dark Al rich phases was Al2O3 phase in Tax1 and Tax3 HIPped samples. High oxygen content of the powder and air leaking in the can during the process of press-seal and welding of the end of the tube of the can prior to HIPping lead to poor consolidation of Tax2 which eventually resulted in high porosity and formation of Ti2O and Al2O3. Half of the Tax2 HIPped sample was canned and heated to 1160 C and was subjected to open die hammer forging with a high strain and a total reduction of height by 66% .The forging produced a pancake shaped sample without breaking of the sample.
Tensile specimens were cut from the Tax1 and Tax3 HIPped sample and one from the Tax2 forged sample using electrical discharge machine (EDM) wirecutting. Tax1 HIPped material showed the average fracture strength of 204MPa, 256MPa and 197MPa at room temperature, 800 C and 900 C respectively., Whereas Tax3 HIPped material showed average fracture strength of 103MPa and 234MPa respectively at room temperature and 800 C respectively. The HIPped and the forged Tax2 sample showed low fracture strength of 91MPa because of the micro-cracks produced during forging.

text: Characterisation, Consolidation and Mechanical Properties of TiAl Alloy Produced Using Titanox Powders Characterization of the three different as- received TiAl powders, namely Tax1, Tax2 and Tax3 produced by Titanox development Ltd has been done. Predominate TiAl phase was observed in all the three compositions .The powder particles were very fine with average particle size of 12μm, 5μm and 10μm respectively for Tax1, Tax2 and Tax3.Chemical analysis of the powders showed high oxygen content in all the three compositions of the powders .
Bulk samples were produced from Tax1, Tax2 and Tax3 powders by hot isostatic pressing at 1200  C under a pressure of 200Mpa for two hours .The pressurization gas used for the process was argon. The relative density of Tax1, Tax2 and Tax3 HIPped samples was 96%, 86% and 93%and respectively. The characterization of the HIPped samples showed that the predominate phase was γ-TiAl phase in all the three HIPped samples .A small fractions of Ti3Al and TiAl3 was also observed in tax1 and Tax3 HIPped material. Also some of the dark Al rich phases was Al2O3 phase in Tax1 and Tax3 HIPped samples. High oxygen content of the powder and air leaking in the can during the process of press-seal and welding of the end of the tube of the can prior to HIPping lead to poor consolidation of Tax2 which eventually resulted in high porosity and formation of Ti2O and Al2O3. Half of the Tax2 HIPped sample was canned and heated to 1160 C and was subjected to open die hammer forging with a high strain and a total reduction of height by 66% .The forging produced a pancake shaped sample without breaking of the sample.
Tensile specimens were cut from the Tax1 and Tax3 HIPped sample and one from the Tax2 forged sample using electrical discharge machine (EDM) wirecutting. Tax1 HIPped material showed the average fracture strength of 204MPa, 256MPa and 197MPa at room temperature, 800 C and 900 C respectively., Whereas Tax3 HIPped material showed average fracture strength of 103MPa and 234MPa respectively at room temperature and 800 C respectively. The HIPped and the forged Tax2 sample showed low fracture strength of 91MPa because of the micro-cracks produced during forging.

year: 2007

title: The use of cellulose in bio-derived formulations for 3D/4D printing: A review

authors: Gauss, Christian

abstract: Cellulose is one of the most versatile biopolymers found in nature. Its use is now transitioning from sustainability-focused development to provide technical solutions across a wide range of applications. This review paper describes the use of cellulose as reinforcement in biocomposites and recent related advances in 3D printing technologies, including 4D (responsive/smart) printing and current/future applications. Relevant aspects such as the origin and intrinsic/structural properties of cellulose and cellulose/matrix interaction during processing are discussed. A particular focus is directed to identify opportunities for the development of new cellulose-based composites, formulation requirements for 3D/4D printing, and comprehension of the interplay between rheology, chemistry, and processing. Overall, new materials and technologies based on cellulose have shown promising results for real-life applications, opening new scientific development opportunities and a new generation of sustainable and advanced materials.

text: The use of cellulose in bio-derived formulations for 3D/4D printing: A review Cellulose is one of the most versatile biopolymers found in nature. Its use is now transitioning from sustainability-focused development to provide technical solutions across a wide range of applications. This review paper describes the use of cellulose as reinforcement in biocomposites and recent related advances in 3D printing technologies, including 4D (responsive/smart) printing and current/future applications. Relevant aspects such as the origin and intrinsic/structural properties of cellulose and cellulose/matrix interaction during processing are discussed. A particular focus is directed to identify opportunities for the development of new cellulose-based composites, formulation requirements for 3D/4D printing, and comprehension of the interplay between rheology, chemistry, and processing. Overall, new materials and technologies based on cellulose have shown promising results for real-life applications, opening new scientific development opportunities and a new generation of sustainable and advanced materials.

year: 2021

title: Book review: Beyond the scene: Landscape and identity in Aotearoa New Zealand – Edited by Janet Stephenson, Mick Abbott and Jacinta Ruru

authors: Beattie, James John

subjects: book review

abstract: This article reviews the book: “Beyond the scene: Landscape and identity in Aotearoa New Zealand”, edited by Janet Stephenson, Mick Abbott and Jacinta Ruru.

text: Book review: Beyond the scene: Landscape and identity in Aotearoa New Zealand – Edited by Janet Stephenson, Mick Abbott and Jacinta Ruru This article reviews the book: “Beyond the scene: Landscape and identity in Aotearoa New Zealand”, edited by Janet Stephenson, Mick Abbott and Jacinta Ruru.

year: 2010-12