Effect of Titanium Depletion of High Temperature Treated NiTi Shape Memory Alloy Wire

2013 ◽  
Vol 467 ◽  
pp. 70-75
Author(s):  
Nazihah Nawawi ◽  
Abdus Samad Mahmud
Keyword(s):  
High Temperature ◽  
Shape Memory ◽  
Heating Temperature ◽  
Temperature Treatment ◽  
Martensite Phase ◽  
High Temperature Treatment ◽  
Niti Shape Memory Alloy ◽  
Volume Percentage ◽  
Outward Diffusion ◽  
The Matrix

Shape memory behaviour of NiTi is very sensitive to the presence of inclusion in the matrix and oxide and the surface. This work studied the influence of high temperature treatment towards thermal martensitic transformation behaviour of NiTi. The alloy was subjected to heat treatment at 1223 K for various times in argon and air environment. It was found that treatment in air severely destroyed the shape memory property of the alloy due to the formation of multilayer of oxides. Treatment in argon also reduced the volume percentage of martensite phase transformation, even though no oxide layer was observed at the surface. This reduction is caused by the depletion of Ti element in the matrix due to the outward diffusion of Ti element. The outward diffusion of Ti is however stabilized at 15 hours exposure time of 1223 K heating temperature.

In Situ TEM Observation of Phase Transformation for Bio-Medical Shape Memory TiNbSn Alloy

2010 ◽  
Vol 152-153 ◽  
pp. 1755-1758
Author(s):  
Yan Li ◽  
Jie Qi ◽  
Rui Rui Fan ◽  
Chuan Xin Zhai ◽  
Chun Hua Xu
Keyword(s):  
Corrosion Resistance ◽  
High Temperature ◽  
Shape Memory ◽  
Martensite Phase ◽  
Unit Cell ◽  
Niti Shape Memory Alloy ◽  
Transformation Mechanism ◽  
Cell Parameters ◽  
Β Phase

TiNbSn alloy has high specific strength, low modulus of elasticity, excellent corrosion resistance, no side effects, such as toxic and exhibits shape memory effects after appropriate technical processing. This alloy may substitute as NiTi shape memory alloy to become the new generation of biological materials. It has been reported the studies of this alloy, such as the component and proportion, processing technology, mechanical properties and corrosion resistance. Based on the previous research, the bio-metal material, Ti-10Nb-5Sn alloy was heated and cooled repeatedly in a heater system located in TEM chamber and, at the same time, was observed in situ using a high resolution transmission electron microscope to study the memory property of the alloy and the mechanism of the transformation between austenite β and martensite phase. The results show that, during heating stage from 295K to 400K, the martensite began to dissolve at 355K, and the martensite disappeared completely at 385K, meanwhile, the austenite was created. During cooling stage from 400K to 295K, the martensite begins to take shape at 353K and the transformation was completed at 333K. The alloy can memory the room and high temperature structures, showing two-way memory functions. The high-temperature austenite of Ti-10Nb-5Sn alloy shows body-centered cubic β phase with the unit cell parameter a=0.3283nm; the martensite at room temperature shows orthorhombic NbTi4 phase (M) with the unit cell parameters a=0.3152nm, b=0.4854nm, c=0.4642nm. The orientation relationship between M phase and β phase is , , , , and . The crystal plane , as the habit plane, transforms into during the transformation from β to M phases. The martensite transformation mechanism is that the and transform to and through the tiny migration of atoms.

An experimental study on the fracture behaviors of marble specimens subjected to high temperature treatment

2020 ◽  
Vol 225 ◽  
pp. 106862 ◽  
Author(s):  
Qingzhen Guo ◽  
Haijian Su ◽  
Jiawei Liu ◽  
Qian Yin ◽  
Hongwen Jing ◽  
...  
Keyword(s):  
Experimental Study ◽  
High Temperature ◽  
Temperature Treatment ◽  
High Temperature Treatment ◽  
Fracture Behaviors

scholarly journals Systemic Infection by Fusarium verticillioides in Maize Plants Grown Under Three Temperature Regimes

Plant Disease ◽  
2008 ◽  
Vol 92 (12) ◽  
pp. 1695-1700 ◽  
Author(s):  
A. Murillo-Williams ◽  
G. P. Munkvold
Keyword(s):  
High Temperature ◽  
Environmental Factors ◽  
Fusarium Verticillioides ◽  
Systemic Infection ◽  
Temperature Treatment ◽  
High Temperature Treatment ◽  
Kernel Infection ◽  
Temperature Regimes ◽  
Maize Plants ◽  
Systemic Development

Fusarium verticillioides causes seedling decay, stalk rot, ear rot, and mycotoxin contamination (primarily fumonisins) in maize. Systemic infection of maize plants by F. verticillioides can lead to kernel infection, but the frequency of this phenomenon has varied widely among experiments. Variation in the incidence of systemic infection has been attributed to environmental factors. In order to better understand the influence of environment, we investigated the effect of temperature on systemic development of F. verticillioides during vegetative and reproductive stages of plant development. Maize seeds were inoculated with a green fluorescent protein-expressing strain of F. verticillioides, and grown in growth chambers under three different temperature regimes. In the vegetative-stage and reproductive-stage experiments, plants were evaluated at tasseling (VT stage), and at physiological maturity (R6 stage), respectively. Independently of the temperature treatment, F. verticillioides was reisolated from nearly 100% of belowground plant tissues. Frequency of reisolation of the inoculated strain declined acropetally in aboveground internodes at all temperature regimes. At VT, the high-temperature treatment had the highest systemic development of F. verticillioides in aboveground tissues. At R6, incidence of systemic infection was greater at both the high- and low-temperature regimes than at the average-temperature regime. F. verticillioides was isolated from higher internodes in plants at R6, compared to stage VT. The seed-inoculated strain was recovered from kernels of mature plants, although incidence of kernel infection did not differ significantly among treatments. During the vegetative growth stages, temperature had a significant effect on systemic development of F. verticillioides in stalks. At R6, the fungus reached higher internodes in the high-temperature treatment, but temperature did not have an effect on the incidence of kernels (either symptomatic or asymptomatic) or ear peduncles infected with the inoculated strain. These results support the role of high temperatures in promoting systemic infection of maize by F. verticillioides, but plant-to-seed transmission may be limited by other environmental factors that interact with temperature during the reproductive stages.

Properties of maraging steels after high-temperature treatment

1981 ◽  
Vol 23 (4) ◽  
pp. 265-267
Author(s):  
O. V. Abramov ◽  
A. I. Il'in ◽  
V. M. Kardonskii
Keyword(s):  
High Temperature ◽  
Temperature Treatment ◽  
High Temperature Treatment ◽  
Maraging Steels
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