title: Evaluation of reactive induction sintering as a manufacturing route for blended elemental Ti-5Al-2.5Fe alloy

authors: Jia, Mingtu

subjects: Science & Technology

abstract: This work focuses on gaining a better understanding of the feasibility of using reactive induction sintering to obtain the alloy Ti-5Al-2.5Fe using Ti, Al and Fe powders (i.e. via a blended elemental approach). For this, powder compacts were induction sintered under various temperature/time combinations like 700–1250 °C and isothermal holding of 0–15 min. Compositional homogeneity, microstructure evolution and mechanical properties of the sintered Ti-5Al-2.5Fe alloy were investigated. It was found that by increasing the sintering temperature and isothermal holding time, sintered Ti-5Al-2.5Fe components with a homogeneous chemical composition and a Widmanstätten microstructure can be produced. The tensile strength increases with the sintering temperature/time reaching comparable values to the wrought alloy; however the residual porosity has a significant impact on the ductility of the alloy. This study demonstrates that reactive induction sintering is suitable to shorten the production route of blended elemental Ti alloys to be used in non-critical applications where ductility is not the main requirement.

text: Evaluation of reactive induction sintering as a manufacturing route for blended elemental Ti-5Al-2.5Fe alloy This work focuses on gaining a better understanding of the feasibility of using reactive induction sintering to obtain the alloy Ti-5Al-2.5Fe using Ti, Al and Fe powders (i.e. via a blended elemental approach). For this, powder compacts were induction sintered under various temperature/time combinations like 700–1250 °C and isothermal holding of 0–15 min. Compositional homogeneity, microstructure evolution and mechanical properties of the sintered Ti-5Al-2.5Fe alloy were investigated. It was found that by increasing the sintering temperature and isothermal holding time, sintered Ti-5Al-2.5Fe components with a homogeneous chemical composition and a Widmanstätten microstructure can be produced. The tensile strength increases with the sintering temperature/time reaching comparable values to the wrought alloy; however the residual porosity has a significant impact on the ductility of the alloy. This study demonstrates that reactive induction sintering is suitable to shorten the production route of blended elemental Ti alloys to be used in non-critical applications where ductility is not the main requirement.

year: 2018

title: Seismic reflection characterisation and geomorphology of the Katikati Basin, Te Awanui (Tauranga Harbour), Aotearoa New Zealand

authors: Mathews, Erin

abstract: Te Awanui (Tauranga Harbour) contains two distinct basins the Katikati Basin in the north, and the Tauranga Basin in the south. The Katikati Basin is not well understood or researched as there is bias towards the Tauranga Basin due to dredging and port activities.

This thesis investigated the Katikati Basin below the surface via a shallow seismic survey and above the surface using historic air photographs and hydrographic charts. No obvious faults were discovered within the seismic survey, therefore the faults found in the Tauranga Basin which are potentially associated with the Taupō rift may not extend into the Katikati Basin. The area surrounding the low gravity anomaly was analysed and there was no clear indication of a caldera therefore the seismic survey did not penetrate deep enough to reach the sediments associated with the low gravity anomaly. The historical air photographs and hydrographic charts showed that most of the changes to the geomorphology occur at the entrance where the tidal inlet has narrowed and deepened and at Waikoura Point on Matakana Island the spit tip changes shape and goes through periods of erosion and accretion especially during a triple-dip La Niña event of the El Niño Southern Oscillation Cycle.

Unfortunately no coring samples were taken within the Katikati basin for this study, therefore the true thickness of the Holocene sediments were not determined however, other studies revealed Holocene sediments up to 20 m in depth which was the depth of this seismic survey therefore I am certain no Pleistocene sediments were reached. There is much more to be researched on the Katikati Basin and this thesis builds as a starting point.

text: Seismic reflection characterisation and geomorphology of the Katikati Basin, Te Awanui (Tauranga Harbour), Aotearoa New Zealand Te Awanui (Tauranga Harbour) contains two distinct basins the Katikati Basin in the north, and the Tauranga Basin in the south. The Katikati Basin is not well understood or researched as there is bias towards the Tauranga Basin due to dredging and port activities.

This thesis investigated the Katikati Basin below the surface via a shallow seismic survey and above the surface using historic air photographs and hydrographic charts. No obvious faults were discovered within the seismic survey, therefore the faults found in the Tauranga Basin which are potentially associated with the Taupō rift may not extend into the Katikati Basin. The area surrounding the low gravity anomaly was analysed and there was no clear indication of a caldera therefore the seismic survey did not penetrate deep enough to reach the sediments associated with the low gravity anomaly. The historical air photographs and hydrographic charts showed that most of the changes to the geomorphology occur at the entrance where the tidal inlet has narrowed and deepened and at Waikoura Point on Matakana Island the spit tip changes shape and goes through periods of erosion and accretion especially during a triple-dip La Niña event of the El Niño Southern Oscillation Cycle.

Unfortunately no coring samples were taken within the Katikati basin for this study, therefore the true thickness of the Holocene sediments were not determined however, other studies revealed Holocene sediments up to 20 m in depth which was the depth of this seismic survey therefore I am certain no Pleistocene sediments were reached. There is much more to be researched on the Katikati Basin and this thesis builds as a starting point.

year: 2024

title: Memento Mori : Memento Maori – moko and memory

authors: Te Awekotuku, Ngahuia

subjects: tangi

abstract: Moko patterns, mau moko, “wearing ink” is often explained as an act of remembrance, a symbol of honour or success, of grieving or loss. Memento mori, remembering the dead and remembrance of death, pervades the Maori world, and is profoundly expressed in customary practice – haehae, upoko tuhi, and ta moko. These embodied and visceral experiences are described in waiata tangi, in whai korero, in moteatea, in the traditional context, and graphically recorded on the living flesh in our contemporary world. Mau moko celebrates identity, so modern memorial ornamentation mourns and reflects on this in ‘memento mori’; and also reinforces and engages reality in the correspondent notion of ‘memento Maori’; an assertion that claims dominion and understanding across generations, across time, across space.

text: Memento Mori : Memento Maori – moko and memory Moko patterns, mau moko, “wearing ink” is often explained as an act of remembrance, a symbol of honour or success, of grieving or loss. Memento mori, remembering the dead and remembrance of death, pervades the Maori world, and is profoundly expressed in customary practice – haehae, upoko tuhi, and ta moko. These embodied and visceral experiences are described in waiata tangi, in whai korero, in moteatea, in the traditional context, and graphically recorded on the living flesh in our contemporary world. Mau moko celebrates identity, so modern memorial ornamentation mourns and reflects on this in ‘memento mori’; and also reinforces and engages reality in the correspondent notion of ‘memento Maori’; an assertion that claims dominion and understanding across generations, across time, across space.

year: 2009-11