Under certain cutting conditions carbide tools can sustain a significant amount of permanent deformation and this may cause early tool failure. Tests were devised to investigate the deformation of three different grades of carbide, when machining steel (817M40, EN24) under a wide range of conditions. Each test was carried out on a continuous (60 seconds) and an incremental (5, 5, 10, 20 and 20 seconds) basis. This plan was adopted to investigate transient effects. During each test the cutting forces were measured with a dynamometer, and the boundary temperatures were measured at the tool/chip interface and the tool/shank interface. The permanent deformation took the form of bulging on the flank face and depression of the rake face. With low metal removal rates the deformation was minimal and the cutting edge was stable. High metal removal rates caused the tool to deform continuously and this gave an unstable cutting edge. It was deduced that within the tool there was a zone of material that had undergone plastic deformation. The rake and flank faces formed two external boundaries of this zone, the remaining boundary being within the tool body. For any particular set of cutting conditions, the amount of deformation for either the continuous test or the total of the incremental tests was essentially the same. A plane stress Finite Element (F.E.) model was developed to explain the effects of speed and feed in terms of temperature and stress and their variation with time. The F.E. model predicted that the values of both the transient and steady state thermal stresses were very low when compared with the mechanical stresses. The results from the cutting tests and the F.E. model suggest that the tool material continuously deformed under the applied mechanical stresses (cutting forces). Any contribution to the deformation from the transient thermal stresses was minimal and of a short duration.

The Avon-Heathcote Estuary, located in Christchurch, New Zealand, experienced coseismic deformation as a result of the February 22nd 2011 Christchurch Earthquake. The deformation is reflected as subsidence in the northern area and uplift in the southern area of the Estuary, in addition to sand volcanoes which forced up sediment throughout the floor of the Estuary altering estuary bed height and tidal flow. The first part of the research involved quantifying the change in the modern benthic foraminifera distribution as a result of the coseismic deformation caused by the February 22nd 2011 earthquake. By analysing the taxa present immediately post deformation and then the taxa present 2 years post deformation a comparison of the benthic foraminifera distribution can be made of the pre and post deformation. Both the northern and the southern areas of the Estuary were sampled to establish whether foraminifera faunas migrated landward or seaward as a result of subsidence and uplift experienced in different areas. There was no statistical change in overall species distribution in the two year time period since the coseismic deformation occurred, however, there were some noticeable changes in foraminifera distribution at BSNS-Z3 showing a landward migration of taxa. The changes that were predicted to occur as a result of the deformation of the Estuary are taking longer than expected to show up in the foraminiferal record and a longer time period is needed to establish these changes. The second stage involved establishing the modern distribution of foraminifera at Settlers Reserve in the southern area of the Avon-Heathcote Estuary by detailed sampling along a 160 m transect. Foraminifera are sensitive to environmental parameters, tidal height, grainsize, pH and salinity were recorded to evaluate the effect these parameters have on distribution. Bray-Curtis two-way cluster analysis was primarily used to assess the distribution pattern of foraminifera. The modern foraminifera distribution is comparable to that of the modern day New Zealand brackish-water benthic foraminifera distribution and includes species not yet found in other studies of the Avon-Heathcote Estuary. Differences in sampling techniques and the restricted intertidal marshland area where the transect samples were collected account for some of the differences seen between this model and past foraminifera studies. xiii The final stage involved sampling a 2.20 m core collected from Settlers Reserve and using the modern foraminiferal distribution to establish a foraminiferal history of Settlers Reserve. As foraminifera are sensitive to tidal height they may record past coseismic deformation events and the core was used to ascertain whether record of past coseismic deformation is preserved in Settlers Reserve sediments. Sampling the core for foraminifera, grainsize, trace metals and carbon material helped to build a story of estuary development. Using the modern foraminiferal distribution and the tidal height information collected, a down core model of past tidal heights was established to determine past rates of change. Foraminifera are not well preserved throughout the core, however, a sudden relative rise in sea level is recorded between 0.25 m and 0.85 m. Using trace metal and isotope analysis to develop an age profile, this sea level rise is interpreted to record coseismic subsidence associated with a palaeoseismic event in the early 1900’s. Overall, although the Avon-Heathcote Estuary experienced clear coseismic deformation as a result of the 22nd of February 2011 earthquake, modern changes in foraminiferal distribution cannot yet be tracked, however, past seismic deformation is identified in a core. The modern transect describes the foraminifera distribution which identifies species that have not been identified in the Avon-Heathcote Estuary before. This thesis enhances the current knowledge of the Avon-Heathcote Estuary and is a baseline for future studies.

Creep is a time-dependent deformation of materials under stress at elevated temperatures. The phenomenon of creep allows materials to plastically deform gradually over time, even at stress levels below its yield point or below its transformation temperature. The issues involving creep are especially significant for magnesium alloys, since they are susceptible to creep deformation from temperatures as low as 100 ºC, which inhibits their potential application in areas such as automotive engines. The University of Canterbury has developed a significant level of experience and infrastructure in the field of Electron Backscatter Diffraction (EBSD). EBSD allows microstructures to be characterized by imaging the crystal structure and its crystallographic orientation at a given point on a specimen surface, whereby the process can be automated to construct a crystallographic “orientation map” of a specimen surface. In light of this, the creep of magnesium and its alloys was studied using a novel technique, in which a conventional tensile creep test was interrupted at periodic intervals, and the EBSD was used to acquire the crystallographic orientation maps repeatedly on a same surface location at each interruption stages. This technique allows simultaneous measurement of the rate of creep deformation and the evolution of the specimen microstructure at various stages of creep, bringing further insight into the deformation mechanisms involved. This thesis summarizes the study of the microstructural and crystallographic texture evolution during creep of pure magnesium and a creep resistant magnesium alloy Mg- 8.5Al-1Ca-0.3Sr. Pure magnesium exhibit a conventional “power-law” type creep, and although its creep properties are well established in the past literatures, there has been little in terms of reconciliation between the observed creep rates and the underlying deformation mechanisms. The alloy Mg-8.5Al-1Ca-0.3Sr, on the other hand, is a modern die casting alloy used in the automotive industry for engine and gearbox applications, and despite its superior creep resistance, little is known about the microstructural contributions to its creep properties. This research was conducted to provide a link between the creep properties, observed microstructures, and theories of creep deformation by the use of advanced microscopy techniques. For the first time, the detailed, sequential microstructural development of magnesium and its alloys during creep has been revealed.

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Elastic deformation has wide applications in medical simulations, therefore when it comes to designing physical behavior of objects for realistic training applications, determining material parameters so that objects behave in a desired way becomes a crucial. In this work we consider the problem of elasticity parameter estimation for deformable bodies, which is important for accurate medical simulations. Our work has two major steps: the first step is the data acquisition and preparation, and the second step is the parameter estimation. The experimental setup for data acquisition consists of depth and force sensors. Surface deformations are acquired as a series of images along with the corresponding applied forces. The contact point of the force sensor on the surface is found visually and the corresponding applied forces are acquired directly from the force sensor. A complete mesh deformation which is obtained from a surface tracking method is employed along with force measurements in the elasticity parameter estimation method. Our approach to estimate the physical material properties is based on an inverse linear finite element method. We have experimented with two approaches to optimize the elasticity parameters: a linear iterative method and a force-displacement error minimization method. The two methods were tested on the simulation data, and the second method was tested on three deformable objects. The results are presented for the data captured by two different depth sensors. The result is a set of two parameters, the Young's modulus and the Poisson's ratio, which represents the stiffness of the object under test.

In order to clarify the dependence of strain localisation on different parameters, a literature survey is presented covering the theory and observations of instability formation during deformation, dynamic recovery processes, mechanical testing, adiabatic heating and shear band formation. Several series of experiments were carried out, on titanium bearing steel and on an austenitic stainless steel , to determine the reasons of the inversion of the dependence of the strain to the peak in flow stress on strain rate observed at high strain rates. The materials were deformed under conditions of plane strain and axisymmetric compression, and torsion. Special techniques were developed in order to measure the distribution of strain and temperature within deforming plane strain specimens. In the strain distribution analysis, it was observed that the range of local strains is dependent on nominal strain rates, but the average value of the local strain either in the whole deforming region or the slip line bands depends only on the value of nominal strain. When the plane strain specimens were deformed with inserted thermocouples, it was found that both the overall temperature increase and the difference in temperature between different local regions of the specimen, increased with the nominal strain rate. It was shown that, at high strain rates, the stress-strain curve of any material will develop a peak in stress as a result of the increase of temperature due to deformational heating, without the occurrence of any strain instability. The results emphasise the complexity of deformation under plane strain compression, particularly at high strain rate, but it was possible to compare stress-strain curves obtained under plane strain and axisymmetric compression conditions when the effects of strain and stress distribution and of temperature localisation were taken into account.