scholarly journals In-situ studies on martensitic transformation and high-temperature shape memory in small volume zirconia

2017 ◽  
Vol 134 ◽  
pp. 257-266 ◽  
Author(s):  
Xiao Mei Zeng ◽  
Zehui Du ◽  
Nobumichi Tamura ◽  
Qing Liu ◽  
Christopher A. Schuh ◽  
...  
Keyword(s):  
High Temperature ◽  
Martensitic Transformation ◽  
Shape Memory ◽  
Small Volume ◽  
In Situ Studies

scholarly journals In Situ Hyperspectral Raman Imaging: A New Method to Investigate Sintering Processes of Ceramic Material at High-temperature

2019 ◽  
Vol 9 (7) ◽  
pp. 1310 ◽  
Author(s):  
Kerstin Hauke ◽  
Johannes Kehren ◽  
Nadine Böhme ◽  
Sinje Zimmer ◽  
Thorsten Geisler
Keyword(s):  
High Temperature ◽  
Raman Imaging ◽  
In Situ Studies ◽  
Kinetic Information ◽  
Novel Approach ◽  
In Situ Investigation ◽  
Dependent Growth ◽  
Micrometer Scale ◽  
Sintering Processes

In the last decades, Raman spectroscopy has become an important tool to identify and investigate minerals, gases, glasses, and organic material at room temperature. In combination with high-temperature and high-pressure devices, however, the in situ investigation of mineral transformation reactions and their kinetics is nowadays also possible. Here, we present a novel approach to in situ studies for the sintering process of silicate ceramics by hyperspectral Raman imaging. This imaging technique allows studying high-temperature solid-solid and/or solid-melt reactions spatially and temporally resolved, and opens up new avenues to study and visualize high-temperature sintering processes in multi-component systems. After describing in detail the methodology, the results of three application examples are presented and discussed. These experiments demonstrate the power of hyperspectral Raman imaging for in situ studies of the mechanism(s) of solid-solid or solid-melt reactions at high-temperature with a micrometer-scale resolution as well as to gain kinetic information from the temperature- and time-dependent growth and breakdown of minerals during isothermal or isochronal sintering.

scholarly journals In-situ TEM Observation of γ→ε Martensitic Transformation during Tensile Straining in an Fe–Mn–Si Shape Memory Alloy

1997 ◽  
Vol 38 (12) ◽  
pp. 1072-1077 ◽  
Author(s):  
Bohong Jiang ◽  
Tsugio Tadaki ◽  
Hirotaro Mori ◽  
T. Y. Hsu (Xu Zuyao)
Keyword(s):  
Martensitic Transformation ◽  
Shape Memory Alloy ◽  
Shape Memory

Martensitic Transformation of High-Entropy and Medium-Entropy Shape Memory Alloys

2021 ◽  
Vol 1016 ◽  
pp. 1802-1810
Author(s):  
Hiromichi Matsuda ◽  
Masayuki Shimojo ◽  
Hideyuki Murakami ◽  
Yoko Yamabe-Mitarai
Keyword(s):  
Solid Solution ◽  
High Temperature ◽  
Martensitic Transformation ◽  
Shape Memory Alloys ◽  
Shape Memory ◽  
Transformation Temperature ◽  
Solid Solution Hardening ◽  
Solution Hardening ◽  
High Entropy ◽  
The One

As new generation of high-temperature shape memory alloys, high-entropy alloys (HEAs) have been attracted for strong solid-solution hardened alloys due to their severe lattice distortion and sluggish diffusion. TiPd is the one potential high-temperature shape memory alloys because of its high martensitic transformation temperature above 500 °C. As constituent elements, Zr expected solid-solution hardening, Pt expected increase of transformation temperature, Au expected keeping transformation temperature, and Co expected not to form harmful phase. By changing the alloy composition slightly, two HEAs and two medium entropy alloys (MEAs) were prepared. Only two MEAs, Ti45Zr5Pd25Pt20Au5, and Ti45Zr5Pd25Pt20Co5 had the martensitic transformation. The perfect recovery was obtained in Ti45Zr5Pd25Pt20Co5 during the repeated thermal cyclic test, training, under 200 MPa. On the other hand, the small irrecoverable strain was remained in Ti45Zr5Pd25Pt20Au5 during the training under 150 MPa because of the small solid-solution hardening effect. It indicates that Ti45Zr5Pd25Pt20Co5 is the one possible HT-SMA working between 342 and 450 °C.

Effect of the Addition of Gd on Ni53Mn22Co6Ga19 High-Temperature Shape Memory Alloy

2010 ◽  
Vol 654-656 ◽  
pp. 2095-2098
Author(s):  
Yun Qing Ma ◽  
Shui Yuan Yang ◽  
San Li Lai ◽  
Shi Wen Tian ◽  
Cui Ping Wang ◽  
...  
Keyword(s):  
Grain Size ◽  
High Temperature ◽  
Martensitic Transformation ◽  
Shape Memory Alloy ◽  
Shape Memory ◽  
Earth Element ◽  
Stress And Strain ◽  
Martensitic Transformation Temperature ◽  
Rich Phase ◽  
Shape Memory Properties

The rare earth element Gd is added to Ni53Mn22Co6Ga19 high-temperature shape memory alloy to refine the grain size and adjust the distribution of γ phase, and their microstructure, martensitic transformation behaviors, mechanical and shape memory properties were investigated. The results show that the grain size is obviously decreased and the γ phase tends to segregate at grain boundaries with increasing Gd content. Small amounts of Gd-rich phase were formed with 0.1 at.% Gd addition. The martensitic transformation temperature abruptly increases with 0.1 at.% Gd addition, then almost keeps constant with further increasing Gd content. The addition of 0.1 at.% Gd is proved to be beneficial to both tensile stress and strain before fracture, but negative to the shape-memory effect.

Temperature Dependence and Martensitic Transformation of Ti50Pt50 Shape Memory Alloys

2014 ◽  
Vol 1019 ◽  
pp. 379-384
Author(s):  
M.P. Mashamaite ◽  
Hasani Rich Chauke ◽  
Rosinah Mahlangu ◽  
P.E. Ngoepe
Keyword(s):  
Molecular Dynamics ◽  
High Temperature ◽  
Martensitic Transformation ◽  
Shape Memory Alloys ◽  
Shape Memory ◽  
Temperature Dependence ◽  
Effect Of Temperature ◽  
Displacive Transformation ◽  
B2 Phase ◽  
Recent Experimental Work

Shape memory alloys (SMAs) are a fascinating group of metals that have two remarkable properties, the shape memory effect and superelasticity. The TiPt structure with the B2 phase has been reported to undergo a reversible displacive transformation to B19 martensite at about 1200K. However, this system could serve in principle as the basis of high-temperature shape memory alloys. Molecular dynamics study of martensitic transformation in platinum titanium alloys was performed to investigate the effect of temperature dependence on B2 and B19 structures at 50 at.%Pt. The NPT ensemble was used to determine the properties of these systems and we found good comparisons with recent experimental work. The temperature dependence of TiPt shows potential martensitic change when B19 is heated to extreme high temperatures of 273K up to 1573K.

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