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Showing 1 to 20 of 20 for “"transformation temperatures"”.
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Low and Structure at Constant Temperature in a Superplastic Fe-Al-Mn-C Alloy.
… original lengths during deformation at elevated temperatures. Micrograin superplasticity is exhibited during deformation at constant temperature by metals having a fine grain structure and is to be distinguished from transformation superplasticity which is exhibited by metals which are repeatedly …
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Materials Processing Towards Development of Rapid Prototyping Technology for Manufacturing Biomedical Implants
… for sub-micron and the agglomerated powder type. Transformation temperatures of tri-calcium phosphate upon cooling were determined as 1475°C for (alpha' to alpha, 1190°C for alpha to beta, and 800--700°C range for beta to hydroxy-oxyapatite transformation. Dilatometry revealed that …
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MODELING OF THERMO-MECHANICAL BEHAVIOR OF NITINOL ACTUATOR FOR SMART NEEDLE APPLICATION
… Two distinct models with different phase transformation kinetic approaches were chosen. The first model was proposed by Terriault and Brailovski (J. Intell. Mat. Systems Structures, 2011) using a modified one dimensional Likhachev formulation. The second model was developed by Brinson (J. …
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Developing a new interatomic potential and atomistic study of NiTiHf
… for implementation in applications at elevated temperatures. Among NiTi-based alloys, NiTiHf has shown to have great potential, by having high transformation temperatures, lower preparation cost and good thermal stability. However, until today, most studies conducted on NiTiHf have focused on a …
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Effects of vanadium microalloying of 1080 steel on pearlite transformation kinetics and microstructural development
The effects of V alloying on the pearlite transformation kinetics and microstructure in 1080 steel were evaluated. Two industrial wire rod steels, 1080 and 1080V with a 0.035 wt pct V addition, were isothermally heat treated using dilatometry to assess pearlite transformation rates. A detailed …
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The Effects of Applied Strain and Heat Treatment on the Properties of NiTi Wire During Shape Setting
… in a salt bath, followed by a rapid quench. Transformation temperatures and mechanical properties were characterized using the differential scanning calorimeter and tensile tests. Changes in the Af, UTS, and elastic modulus due to ageing processes and applied strain were observed. Following …
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Commissioning Of An Arc-melting/vacuum Quench Furnace Facility For Fabrication Of Ni-ti-fe Shape Memory Alloys, And The Characterization
… as high as 8%. Heating results in a phase transformation and associated recovery of all the accumulated strain, a phenomenon known as shape memory. This strain recovery can occur against large forces, resulting in their use as actuators. The goal of this project is to lower the operating …
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The influence of substitutional elements on the transformability of 3CR12 steel
… found in 3CR12, whilst accelerating the transformation to alpha ferrite might eliminate the need for an annealing treatment. Volume fraction analysis (VF A) of specimens quenched from a soaking temperature of 1000°C showed that Co, Ni and Cu stabilise austenite, whilst Si and Al have the …
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Towards Crack-Resistant Polycrystalline Zirconia Shape-Memory Ceramics with Low Hysteresis
… ceramics, which offer higher work output, transformation temperatures, and possibly environmental resistance compared to metallic shape-memory alloys. Despite these potential benefits, two shortcomings have prevented these materials from reaching their full potential: i) polycrystals …
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An Investigation of the Structural and Magnetic Transitions in Ni-Fe-Ga Ferromagnetic Shape Memory Alloys
The martensite and magnetic transformations in Ni-Fe-Ga ferromagnetic shape memory alloys are very sensitive to both alloy chemistry and thermal history. A series of Ni-Fe-Ga alloys near the prototype Heusler composition (X2YZ) were fabricated and homogenized at 1423 °K, and a Ni₅₃Fe₁₉Ga₂₈ alloy …
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An investigation into the influence of microstructural condition on the superelastic behaviour in Ti-Nb-based alloys.
… and shape memory properties over a wide range of temperatures, making them attractive for industrial applications. However, within the literature there are significant variations in the reported martensite start temperatures that have not been rationalised. To investigate the source of these …
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A constitutional study of a dual phase steel containing 12% chromium
… included the detennination of time-temperature-transformation (TTT) diagrams for the transformations between austenite and ferrite and an investigation into the factors controlling these reactions. The austenite decomposition reaction for a high nickel alloy, 3CR12Ni, and the effect of varying …
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Effect of heat treatment on the microstructure of a 2CrMoNiWV rotor steel
… on microstructural change, alloy carbide transformation mechanism and mechanical properties. Two complete continuous cooling transformation (CCT) diagrams were constructed for this steel on the basis of experimental dilatometry thermal analysis, metallographic examination and current phase …
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Atomistic to Continuum Multiscale and Multiphysics Simulation of NiTi Shape Memory Alloy
… diffusionless, displacive (solid to solid) phase transformation, due to the application of temperature and/ or stress (/strain). Among different SMAs, NiTi is a popular one. NiTi shows reversible phase transformation, the shape memory effect (SME), where irreversible deformations are recovered …
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Size Effects in Shape Memory Ceramics
… ceramics (SMCs) are attractive for their high transformation temperatures and transformation stresses compared to shape memory metals but exhibit transformation-induced cracking due to mismatch stresses arising at the grain boundaries. Current strategies for mitigating cracking in SMCs involve …
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Instrumented Nanoindentation Studies Of Deformation In Shape Memory Alloys
… as mechanical twinning and stress induced phase transformation between a high symmetry phase (austenite) and a low symmetry phase (martensite) additionally occur and influence mechanical behavior and thus their functionality. Consequently, applications of SMAs usually call for precise phase …
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Modification and Integration of Shape Memory Alloys Through Thermal Treatments and Dissimilar Metal Joining
… for control over martensitic microstructure, transformation temperatures, and shape memory recovery. Modifications to shape memory properties are investigated through the use of temperature-dependent optical microscopy, temperature-dependent X-ray diffraction, and nano-indentation. As shape …
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The characteristics of Titanium-nickel alloys produced by powder technology
… and heat treatment on micro hardness and transformation temperature (M<sub>s</sub>) is described.<br></br><br></br>During sintering, anisotropy of dimensional change occurs, with expansion in the radial and contraction in the axial direction of cylindrical compacts. Greater porosity is …
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Microstructural Evolution in Refractory Metal Multi-Component Alloy Systems
… efficiency targets demand higher operating temperatures than those tolerated by current Ni-based superalloys, motivating the search for alternative high temperature materials. Refractory superalloys based on AlTaTiZr and AlMoNbTaTiZr have attracted particular interest, as early studies …
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On the thermomechanics of localizing pseudoelastic transformations in NiTi materials and structures
… NiTi alloys undergo reversible solid-state transformations around room temperature, which are activated by the application of stress or by modest temperature changes. The forward transformation causes about 6% strain and the release of about 12 kJ/kg of latent heat; both are recovered during …