Effect of low-temperature aging treatment on thermally- and stress-induced phase transformations of nanocrystalline and coarse-grained NiTi wires

2017 ◽  
Vol 131 ◽  
pp. 49-59 ◽  
Author(s):  
Bo Sun ◽  
M.W. Fu ◽  
Jianping Lin ◽  
Y.Q. Ning
Keyword(s):  
Low Temperature ◽  
Phase Transformations ◽  
Aging Treatment ◽  
Coarse Grained ◽  
Low Temperature Aging ◽  
Niti Wires ◽  
Temperature Aging

Effect of Low-Temperature Aging on Thermally-Induced Phase Transformation of NiTi Wire with a Wide Range of Grain Sizes

2021 ◽  
Vol 1042 ◽  
pp. 9-16
Author(s):  
Zhi Hao Zhao ◽  
Jian Ping Lin ◽  
Jun Ying Min ◽  
Yong Hou ◽  
Bo Sun
Keyword(s):  
Grain Size ◽  
Phase Transformation ◽  
Low Temperature ◽  
Thermally Induced ◽  
Grain Sizes ◽  
Average Grain Size ◽  
Wide Range ◽  
Low Temperature Aging ◽  
Niti Wires ◽  
Temperature Aging

Thermally-induced phase transformation (PT) is of significance and value to the application of NiTi alloy components. Low-temperature aging (LTA) treatment was used to alter PT characteristics of NiTi alloys avoiding undesirable grain growth. Effect of LTA on PT of NiTi wires with a wide range of grain sizes from 34 nm to 8021 nm was investigated in this study. As the average grain size varies from 34 to 217 nm, the temperature of the B2↔R transformation increase as a result of LTA, and the increasing effect is more obvious at a larger grain size. For NiTi alloys with average grain sizes ranging from 523 to 1106 nm, transformation sequence changes from B2↔B19' to B2↔R due to LTA. For the sample with an average grain size of 2190 nm, the B2↔B19' transformation is replaced by B2↔R←B19' after LTA. When the average grain size is larger than 2190 nm, transformation sequence changes from B2↔B19' to B2↔R↔B19' after LTA. Transmission emission microscope observations reveal that the above-mentioned PT behavior correlates with the coupled effect of grain size and precipitation. The precipitation of Ni4Ti3 in the grains with a size smaller than ~150 nm is inhibited after LTA, the temperature of B2→R of samples with average GS smaller than ~150 nm still is elevated due to the inhomogeneous grain size of NiTi wires.

scholarly journals A Novel Design to Enhance the Mechanical Properties in Cu-Bearing Antibacterial Stainless Steel

Materials ◽  
2020 ◽  
Vol 13 (2) ◽  
pp. 403
Author(s):  
Shaoheng Sun ◽  
Zhiyong Xue ◽  
Licong An ◽  
Xiaohua Chen ◽  
Yifei Liu
Keyword(s):  
Stainless Steel ◽  
Low Temperature ◽  
Antibacterial Properties ◽  
Aging Treatment ◽  
Copper Precipitation ◽  
The Matrix ◽  
Novel Method ◽  
Low Temperature Aging ◽  
Novel Design ◽  
Temperature Aging

A novel method based on nano-scale precipitation hardening has been studied to strengthen copper-bearing ferrite antibacterial stainless steel. Bimodal precipitations can be observed after antibacterial annealing and low temperature aging treatment, which are large rod-shaped precipitates and nano-sized spherical precipitates, respectively. Due to two different morphological precipitates, the strength of the material is significantly improved without sacrificing formability, and at the same time, the excellent antibacterial properties remain. Under low temperature aging treatment, there is no obvious evidence to show the segregation at the interface between the rod-shaped copper precipitation and the matrix due to the low segregation coefficient of copper. The nano-sized copper precipitation uniformly nucleated and distributed on the matrix. The optimized heat treatment process is antibacterial annealing at 800 °C for half an hour followed by one-hour-aging treatment at 550 °C.

Balance of mechanical properties of Mg-8Li-3Al-2Zn-0.5Y alloy by solution and low-temperature aging treatment

2019 ◽  
Vol 791 ◽  
pp. 655-664 ◽  
Author(s):  
Hao Ji ◽  
Xiang Peng ◽  
Xiaolong Zhang ◽  
Wencai Liu ◽  
Guohua Wu ◽  
...  
Keyword(s):  
Mechanical Properties ◽  
Low Temperature ◽  
Aging Treatment ◽  
Low Temperature Aging ◽  
Temperature Aging

Microbiological Studies on Aging of Intact and Excised Beef Muscle1

1978 ◽  
Vol 41 (4) ◽  
pp. 259-262 ◽  
Author(s):  
C. R. REY ◽  
A. A. KRAFT ◽  
F. C. PARRISH
Keyword(s):  
High Temperature ◽  
Low Temperature ◽  
Room Temperature ◽  
Aging Treatment ◽  
Bacterial Populations ◽  
Similar Treatment ◽  
Low Temperature Aging ◽  
Retail Cuts ◽  
The University ◽  
Temperature Aging

Beef cattle from the University herd were used for these studies; aging treatments after slaughter were as follows: (a) sides were held at room temperature (21–23 C), (b) sides were held at 2 C, (c) sides were kept for 6 hat room temperature and then the round was removed and placed at 2 C for 18 h (d) sides were held for 3 days at 2 C, then the excised round was kept for 4 days at 2 C for a total of 1 week of low temperature aging. After aging by procedures described, steaks were cut from the round, packaged and stored in a display case at about 5 C. Similar treatment was given to ground beef prepared from the same round muscles. Holding an entire side of beef at high temperature for 24 h promoted bacterial growth on the surface with subsequent proliferation on retail cuts. Shortening the aging treatment at high temperature resulted in reduced bacterial populations on packaged items. Highest bacterial loads and most rapid spoilage resulted from excising the muscle after low temperature holding and then continuing to hold the muscle in the cooler. This treatment was even more conducive to spoilage than was holding at room temperature for 24 h, and is not to be recommended.

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