scholarly journals Effect of Stoichiometry on Shape Memory Properties of Ti-Ni-Hf-Cu-Nb Shape Memory Alloys Manufactured by Suspended Droplet Alloying

Solids ◽  
2022 ◽  
Vol 3 (1) ◽  
pp. 1-21
Author(s):  
Sheng Li ◽  
Minshi Wang ◽  
Khamis Essa ◽  
Chunlei Gan ◽  
Chunyan Liu ◽  
...  
Keyword(s):  
Shape Memory ◽  
Transformation Temperature ◽  
Synthesis Method ◽  
Negative Influence ◽  
Alloying Elements ◽  
Cycle Stability ◽  
Different Types ◽  
The Matrix ◽  
Negative Effect ◽  
Suspended Droplet

A novel Ti-Ni-Hf-Cu-Nb shape memory alloy has been developed by a new combinatorial alloy synthesis method, the Suspended Droplet Alloying. The influence of alloying elements on the transformation temperature, the microstructure and the shape memory effect of this alloy have also been studied. It was found that Cu has a greater negative influence on the transformation temperature of Ti-Ni-Hf-CuX alloys (about −5 K/at.%) than on the Ti-Ni-CuX alloys (−0.67 K/at.%). In addition, the negative effect intensifies with increasing Hf content. The transformation temperature rapidly decreases with increasing Nb composition in the Ti-Ni-Cu-Nb and Ti-Ni-Hf-Cu-Nb alloys, with the solid solution of Nb in the matrix being 1 at.%. A Ti-Ni-Cu-Hf-Nb alloy with high thermal cycle stability has been developed, where the alloying elements affect the transformation behaviour via altering the slipping energy and forming different types of precipitations.

EFFECT OF ANNEALING ON SHAPE MEMORY CHARACTERISTICS OF Ti-50.85at.%Ni ALLOY

2008 ◽  
Vol 01 (03) ◽  
pp. 209-213 ◽  
Author(s):  
J. I. KIM ◽  
T. H. NAM ◽  
Y. J. LEE ◽  
S. MIYAZAKI
Keyword(s):  
Shape Memory ◽  
Transformation Temperature ◽  
Annealing Temperature ◽  
Tensile Tests ◽  
Phase Transformation Temperature ◽  
Martensitic Transformation Temperature ◽  
Ni Alloy ◽  
The Matrix ◽  
Cold Worked ◽  
Memory Characteristics

In order to clarify the effect of annealing on the shape memory behavior of Ti -50.85at.% Ni alloy, the deformation and transformation behavior were investigated using tensile tests and differential scanning calorimeter (DSC). The martensitic transformation temperature increases with increasing annealing temperature until it reach as a maximum, and then decreases with further increasing annealing temperature. This can be rationalized by interaction between the distribution of Ti 3 Ni 4 precipitates and recovery of cold-worked structure. The R-phase transformation temperature increases with increasing annealing temperature until reaching a maximum, and then decreases with a further increase of annealing temperature. This is attributed to the change of Ni content in the matrix caused by precipitation of Ti 3 Ni 4. The critical stress for slip decreases rapidly with increasing annealing temperature, influenced by interaction between the distribution of Ti 3 Ni 4 precipitates and recovery of cold-worked structure.

scholarly journals TiPd- and TiPt-Based High-Temperature Shape Memory Alloys: A Review on Recent Advances

Metals ◽  
2020 ◽  
Vol 10 (11) ◽  
pp. 1531
Author(s):  
Yoko Yamabe-Mitarai
Keyword(s):  
High Temperature ◽  
Martensitic Transformation ◽  
Shape Memory Alloys ◽  
Shape Memory ◽  
Transformation Temperature ◽  
Ternary Alloys ◽  
Alloying Elements ◽  
Martensitic Transformation Temperature ◽  
High Entropy ◽  
Perfect Recovery

In this paper high-temperature shape memory alloys based on TiPd and TiPt are reviewed. The effect of the alloying elements in ternary TiPd and TiPt alloys on phase transformation and strain recovery is also discussed. Generally, the addition of alloying elements decreases the martensitic transformation temperature and improves the strength of the martensite and austenite phases. Additionally, it also decreases irrecoverable strain, but without perfect recovery due to plastic deformation. With the aim to improve the strength of high-temperature shape memory alloys, multi-component alloys, including medium- and high-entropy alloys, have been investigated and proposed as new structural materials. Notably, it was discovered that the martensitic transformation temperature could be controlled through a combination of the constituent elements and alloys with high austenite finish temperatures above 500 °C. The irrecoverable strain decreased in the multi-component alloys compared with the ternary alloys. The repeated thermal cyclic test was effective toward obtaining perfect strain recoveries in multi-component alloys, which could be good candidates for high-temperature shape memory alloys.

The Influence of Stress and Heat on the Transformation Behaviour of NiTi for Actuator Applications in Extruded Aluminium Matrix Composites

2015 ◽  
Vol 825-826 ◽  
pp. 205-212 ◽  
Author(s):  
Pascal Pinter ◽  
Andreas Reeb ◽  
Kay André Weidenmann
Keyword(s):  
Shape Memory ◽  
Transformation Temperature ◽  
Matrix Material ◽  
Extrusion Process ◽  
Matrix Composites ◽  
Lightweight Structures ◽  
Wide Range ◽  
The Matrix ◽  
Single Production ◽  
And Control

The integration of functions in lightweight structures features great potential for future applications in diagnosis and control. The combination of shape memory wires or ribbons made of NiTi embedded in aluminium and manufactured by composite extrusion offers the possibility to produce a composite actuator material in a single production step. The extrusion process allows a wide range of shapes and provides higher versatility than actuators made of bi-metals. The transformation temperature of NiTi varies depending on the composition of the alloy, between -100 °C and 100 °C. However, NiTi can also transform stress-induced. In the designated application, a force is applied via the interface onto the matrix material to deform it. Due to the resulting stress, the transformation temperature rises to temperatures higher than those of the unloaded material. Furthermore the production of composite extrusions leads to a significant heat input on the shape memory alloys followed by another increase of the transformation temperature.Therefore it is essential to reproduce the heat treatment and the stress-induced transformation to predict the transformation temperature in the resulting composite influenced by the interface. For that purpose, the wire gets annealed in a furnace with different durations at a temperature similar to that of the bar extrusion process. After this, the transformation temperatures can be observed at various stresses to evaluate their applicability for aluminium composite actuators.

scholarly journals Systematic Review of Alexithymia in the Population of Hemodialysis Patients

2021 ◽  
Vol 10 (13) ◽  
pp. 2862
Author(s):  
Đorđe Pojatić ◽  
Ivana Tolj ◽  
Davorin Pezerović ◽  
Dunja Degmečić
Keyword(s):  
Mental Health ◽  
Literature Review ◽  
Web Of Science ◽  
Major Effect ◽  
Hemodialysis Patients ◽  
Bibliographic Databases ◽  
Inclusion Criteria ◽  
The Matrix ◽  
Negative Effect ◽  
Bodily Sensations

Alexithymia is a construct defined as the inability to differentiate between emotional experiences and bodily sensations. According to existing knowledge, alexithymia may have a major effect on the process of treatment and the outcome of the hemodialysis disease. The objective of this literature review was to determine the significance that alexithymia has for compliance and variables of clinical and mental health in the population of hemodialysis patients. For the above purpose, bibliographic databases “MEDLINE” and “Web of Science” were searched. The matrix method was used in analysis of articles. Searching both databases resulted in 248 articles. After applying exclusion and inclusion criteria, we included results of 13 articles in the literature review. The results of the search are findings regarding the prevalence and correlation of alexithymia with variables of clinical and mental health in hemodialysis patients. Alexithymia is significantly more common in the population of hemodialysis patients, and it has a negative effect on their mental and somatic health. Alexithymia levels in hemodialysis patients are more pronounced in cases where there is a greater number of comorbidities. Alexithymia is the predictor of high mortality rate in the population of hemodialysis patients, independent of other comorbidities.

Effects of ball properties on throwing in young team-handball beginners

2021 ◽  
pp. 174795412110236
Author(s):  
Frowin Fasold ◽  
Benjamin Noël ◽  
André Nicklas ◽  
Fabian Lukac ◽  
Stefanie Klatt
Keyword(s):  
Experimental Study ◽  
Movement Patterns ◽  
Team Handball ◽  
Throwing Accuracy ◽  
Different Types ◽  
Negative Effect ◽  
Study Participants

Throwing a ball is a primary skill in team-handball and can be directly influenced by the properties of different types of balls. Therefore, the use of different balls (i.e., methodic ball) recommended by the handball federations (e.g., IHF) and the education guidelines, are important in teaching throwing. Previous studies have shown that movement patterns and throwing velocity can be influenced by different ball types and sizes. However, the influence of these factors on throwing accuracy has not been investigated in detail yet. This study aims to replicate the findings of previous studies on increasing throwing velocity in children by comparing the use of a soft methodic ball with a size 0 handball. Furthermore, this study investigates the influence of these balls on throwing accuracy. In an experimental study, participants (10-years of age) threw a soft methodic ball and a size 0 ball at target areas in a handball goal. For all the throws, throwing velocity and accuracy were measured. Commensurate with previous research, throwing velocity was higher for the soft methodic ball compared to a size 0 ball. No difference was found in accuracy, although, it is worth mentioning that the participants were only experienced in throwing using the size 0 ball. Moreover, only one-third of the children favored throwing with a size 0 ball, which is what they are used to in training and competition. The results of our study, therefore, confirm that using soft methodic balls additionally, positively influences the throwing velocity and has no negative effect on the accuracy in throwing among young handball beginners.

High Temperature Mechanical Properties of Ni-Al-Cr Based Alloys with Refractory Alloying Elements

2006 ◽  
Vol 510-511 ◽  
pp. 358-361
Author(s):  
Won Yong Kim ◽  
Han Sol Kim ◽  
In Dong Yeo ◽  
Mok Soon Kim
Keyword(s):  
High Temperature ◽  
Volume Fraction ◽  
Lattice Parameter ◽  
Alloying Elements ◽  
Solid Solution Hardening ◽  
High Temperature Strength ◽  
High Temperature Mechanical Properties ◽  
Die Materials ◽  
The Matrix ◽  
Effective Role

We report on advanced Ni3Al based high temperature structural alloys with refractory alloying elements such as Zr and Mo to be apllied in the fields of die-casting and high temperature press forming as die materials. The duplex microstructure consisting of L12 structured Ni3Al phase and Ni5Zr intermetallic dispersoids was observed to display the microstructural feature for the present alloys investigated. Depending on alloying elements, the volume fraction of 2nd phase was measured to be different, indicating a difference in solid solubility of alloying elements in the matrix γ’ phase. Lattice parameter of matrix phase increased with increasing content of alloying elements. In the higher temperature region more than 973K, the present alloys appeared to show their higher strength compared to those obtained in conventional superalloys. On the basis of experimental results obtained, it is suggested that refractory alloying elements have an effective role to improve the high temperature strength in terms of enhanced thermal stability and solid solution hardening.

Determination of crystallinity of Chinese handmade papers by means of X-ray diffraction

2020 ◽  
Vol 41 (2) ◽  
pp. 69-86
Author(s):  
Peng Liu ◽  
Hongbin Zhang ◽  
Sinong Wang ◽  
Hui Yu ◽  
Bingjie Lu ◽  
...  
Keyword(s):  
Negative Influence ◽  
X Ray Diffraction ◽  
Cross Sectional ◽  
X Ray ◽  
Eulaliopsis Binata ◽  
Different Types ◽  
Powder Samples ◽  
Xrd Patterns ◽  
Xrd Method

AbstractThe crystallinity indices (CrI) of Chinese handmade papers were investigated using the X-ray diffraction (XRD) method. Four Chinese handmade papers, Yingchun, Zhuma, Yuanshu and Longxucao papers were used as model substrates of mulberry bark, ramie, bamboo and Eulaliopsis binata papers, respectively. Two forms of the paper samples, paper sheets and their comminuted powders, were used in this study. The results showed that their XRD patterns belong to the cellulose-I type and Iβ dominates the cellulose microstructure of these paper samples. Moreover, it was found that the microstructures and CrIs of cellulose of these papers were changed by the grinding treatment. This work suggested that the sheet form of the handmade papers is suitable to determine CrI by XRD, despite the contribution of non-cellulosic components in the papers. The order of CrIs for these paper sheet samples was Yingchun, Zhuma, Longxucao and Yuanshu papers. Besides CrIs, differences in cross-sectional areas of the crystalline zone of cellulose can be used for comparing different types of handmade papers. It was also found that the CrIs and crystallite size of paper cellulose varied between the sheet samples and the powder samples, illustrating that the pulverisation has a negative influence on the microstructure of the handmade papers.

Self-propagating high-temperature synthesis microalloying of MoSi2 with Nb and V

2003 ◽  
Vol 18 (8) ◽  
pp. 1842-1848 ◽  
Author(s):  
F. Maglia ◽  
C. Milanese ◽  
U. Anselmi-Tamburini ◽  
Z. A. Munir
Keyword(s):  
Solid Solution ◽  
High Temperature ◽  
Tetragonal Phase ◽  
Synthesis Method ◽  
The Self ◽  
Alloying Elements ◽  
Alloying Element ◽  
Temperature Synthesis ◽  
Starting Mixture ◽  
High Temperature Synthesis

Microalloying of MoSi2 to form Mo(1−x)MexSi2 (Me = Nb or V) was investigated by the self-propagating high-temperature synthesis method. With alloying element contents up to 5 at.%, a homogeneous C11b solid solution was obtained. For higher contents of alloying elements, the product contained both the C11b and the hexagonal C40 phases. The relative amount of the C40 phase increases with an increase in the content of alloying metals in the starting mixture. The alloying element content in the hexagonal C40 Mo(1−x)MexSi2 phase was nearly constant at a level of about 12 at.% for all starting compositions. In contrast, the content of the alloying elements in the tetragonal phase is considerably lower (around 4 at.%) and increases slightly as the Me content in the starting mixture is increased.

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