scholarly journals Metallic alloy with shape memory – selected properties and engineering aspects

2019 ◽  
Author(s):  
Krzysztof Kuś ◽  
Adam Frączyk ◽  
Adam Wojtkowiak
Keyword(s):  
Heat Treatment ◽  
High Temperature ◽  
Shape Memory ◽  
Experimental Studies ◽  
Point Of View ◽  
Ti Alloy ◽  
Practical Application ◽  
Technical Aspects ◽  
Technical Point ◽  
The Veil

In the case of shape memory alloys (SMA), a form to which a material is expected to return during its heating can be repeatedly programmed, whereas other related properties also individually adjusted. It was noticed that most producers of commercial assortment based on SMA or traders seldom are willing to lift the veil of secrecy on this topic. In the context of own experimental studies, the authors made reference to technical aspects of some post-treatments of a Ni-Ti alloy with a view to further practical application, e.g. design and construction of machinery and structures with the involvement of SMA. For these purposes, attempts concerning the high-temperature shape setting were carried out using various parameters of heat treatment with no secrecy surrounding the procedures applied. Some of the tested parameters proved effective, whereas some were less useful. Following the activation of the reverse transformation by heating, a somewhat different behaviour was observed, and simultaneously one of the crucial material temperatures was determined. The paper as a whole is reported from a specifically engineering/technical point of view, which is continuously emphasized in the content of the presented article.

scholarly journals High-temperature multilevel sterilization of canned goods with heat recovery and its constructive and technological support

2021 ◽  
Vol 247 ◽  
pp. 01030
Author(s):  
Mafiiat Rakhmanova ◽  
Amiiat Demirova ◽  
Magomed Akhmedov ◽  
Faina Azimova ◽  
Irada Gadzhibekova ◽  
...  
Keyword(s):  
Heat Treatment ◽  
High Temperature ◽  
Heat Recovery ◽  
Experimental Studies ◽  
Cooling Water ◽  
Practical Implementation ◽  
Canned Food ◽  
Significant Saving ◽  
Technological Support ◽  
Thermal Sterilization

New technical solutions improving the process of thermal sterilization of canned products through the use of multilevel high-temperature modes and heat recovery have been considered and proposed. The essence of the developed method lies in the fact that the heat released by cooling cans with the product that has undergone thermal sterilization is used to heat other cans with the product queued for sterilization. In this mode of heat treatment, except in the last stage, the heat emitted by cooled cans that have already undergone heat treatment is used to heat up the canned food. Hence, the use of the principle of heat recovery by cooling canned products in the baths where others are simultaneously heated provides a significant saving of heat energy and water. Depending on the temperature parameters at different stages of the heat treatment, the heat recovery rate can reach up to 90%. The method also provides savings on cooling water. For the practical implementation of the developed method, the design of the device for multilevel high-temperature thermal sterilization of canned food with heat recovery has been developed. On the basis of experimental studies, new, multilevel high-temperature modes of apple compote sterilization have been developed.

scholarly journals Complete laparoscopic pancreaticoduodenectomy: our experience of the first case

2019 ◽  
Vol 22 (1) ◽  
pp. 26-30
Author(s):  
Mukund Raj Joshi ◽  
Sujan Regmee ◽  
Tanka Prasad Bohara ◽  
Rupesh Chakradhar ◽  
Mandesh Shrestha
Keyword(s):  
Blood Loss ◽  
Point Of View ◽  
Resected Specimen ◽  
Laparoscopic Pancreaticoduodenectomy ◽  
Technical Aspects ◽  
Technical Point ◽  
Operative Outcomes ◽  
Post Operative Period ◽  
First Case

Laparoscopic pancreaticoduodenectomy was described in 1994. It is considered the most challenging abdominal surgery. Although the procedure was found to be feasible in initial reports, the benefits were not considered favorable. In recent days, with the increasing experience of surgeons, acceptable outcomes are being observed and have been found to be technically beneficial and oncologically safe in selective cases in experienced hands. We performed the procedure in a 42-year-old gentleman with good operative and post-operative outcomes. The patient’s follow-up for six post-operative months seems satisfactory. The operation took 840 minutes with minimal blood loss. The resected specimen was adequate and satisfactory from an oncological and technical point of view. The patient developed some inherent complications of the procedure in the post-operative period. He recovered well. Details of the case and technical aspects are being discussed.  

3. On the Crystallization of Silica from Fused Metals

1882 ◽  
Vol 11 ◽  
pp. 37-40 ◽  
Author(s):  
R. Sydney Marsden
Keyword(s):  
High Temperature ◽  
Point Of View ◽  
Considerable Importance ◽  
Slow Cooling ◽  
Technical Point ◽  
The Subject

The crystallization of silica from fused metals, although at first sight appearing to be of little importance, nevertheless presents some features of peculiar interest. It also constitutes a field almost entirely new to the investigator, though the subject is one which, from a technical point of view, may prove to be of very considerable importance.I have therefore undertaken the examination of some of the facts relating to this subject—at first more particularly inquiring into the nature of the change which occurs when silica itself is kept at a high temperature for a number of hours and subsequently submitted to a process of very slow cooling.

High Temperature Compression Properties of Ni3(Si,Ti) Based Intermetallic Compounds

2014 ◽  
Vol 783-786 ◽  
pp. 1129-1135
Author(s):  
Takehito Hagisawa ◽  
Hirokazu Madarame ◽  
Shinji Tanaka ◽  
Yasuyuki Kaneno ◽  
Takayuki Takasugi
Keyword(s):  
Heat Treatment ◽  
Solid Solution ◽  
High Temperature ◽  
Strain Rate ◽  
Volume Fraction ◽  
Solution Phase ◽  
Solid Solution Phase ◽  
Ti Alloy ◽  
Compression Properties ◽  
Ti Alloys

High temperature compression properties of Al-, Cr-or Nb-added Ni3(Si,Ti) based intermetallic compounds were investigated by uni-axial compression test and microstructural observation. The Al-or Cr-added Ni3(Si,Ti) alloys after homogenization heat treatment exhibited a two-phase microstructure consisting of L12and Ni-solid solution phases. The Nb-added Ni3(Si,Ti) alloy after homogenization heat treatment exhibited a triple-phase microstructure consisting of G-phase with D8a structure and Ni-solid solution phase in the L12matrix. The volume fraction of Ni-solid solution phase increased in order of Cr-, Nb-and Al-added Ni3(Si,Ti) alloys. The Cr-added Ni3(Si,Ti) alloy was deformable at high strain rate, while the Nb-added one was deformable at low strain rate. It can be considered that the deformability of Ni3(Si,Ti) at high temperature is closely correlated with volume fraction of Ni-solid solution phase and recrystallization behavior.

High Temperature Annealing of Simox Layers Physical Mechanisms of Oxygen Segregation

1988 ◽  
Vol 100 ◽  
Author(s):  
C. Jaussaud ◽  
J. Margail ◽  
J. Stoemenos ◽  
M. Bruel
Keyword(s):  
Heat Treatment ◽  
High Temperature ◽  
Concentration Profile ◽  
Point Of View ◽  
High Temperature Annealing ◽  
Physical Mechanisms ◽  
Oxygen Migration ◽  
Buried Layer

ABSTRACTHigh temperature annealing of Simox wafers (T > 1300°C), has been proved to dramaticaly increase the quality of the SOI structure.The heat treatment leads to a redistribution of the implanted oxygen, opposite to its concentration profile, towards the buried layer.This paper describes from a thermodynamical point of view the SiO2 precipitates dissolution. The physical mechanisms of the oxygen migration are also discussed.

scholarly journals Упругие свойства сплавов TiNi с памятью формы с различной термообработкой

2019 ◽  
Vol 61 (7) ◽  
pp. 1223
Author(s):  
З.А. Казей ◽  
В.В. Снегирев
Keyword(s):  
Crystal Structure ◽  
Heat Treatment ◽  
Internal Friction ◽  
Shape Memory ◽  
Experimental Studies ◽  
Martensitic Transition ◽  
Additional Heat ◽  
Heating And Cooling ◽  
Elastic Anomalies ◽  
Elastic Characteristics

Comparative experimental studies of the elastic characteristics of commercial shape memory TiNi alloys (Nitinol) exposed to different heat treatment have been carried out within the (80 - 300) K temperature range, including the points of premartensitic and martensitic transitions. It was found that the distortion of the crystal structure at the premartensitic transition in the “as prepared” sample is accompanied by pronounced anomalies of the Young's modulus and internal friction. This transition occurs at TS ≈ 270 K both upon heating and cooling. After an additional heat treatment, the premartensitic transition temperatures TSu and TSd upon heating and cooling respectively, shift slightly and the hysteresis turns out to be more pronounced. However, the form of elastic anomalies remains nearly the same. In contrast, for the martensitic transition at T ≈ 220 K, the elastic anomalies are observed only upon cooling, and the temperature and shape of these anomalies undergo significant changes under effect of the heat treatment.

Kinetics of Residual Stresses in a Welded Frameless Tubular Node

2019 ◽  
Vol 946 ◽  
pp. 921-927
Author(s):  
A.K. Tingaev
Keyword(s):  
High Temperature ◽  
Yield Strength ◽  
Residual Stresses ◽  
Heat Affected Zone ◽  
Strength Class ◽  
Experimental Studies ◽  
Point Of View ◽  
Maximum Value ◽  
Effective Reduction ◽  
Kinetics Of

The results of experimental studies of the variation of residual stresses in a frameless tubular node of the offshore stationary platform (OSP) due to technological effects on the metal are presented. It is shown in the paper that the value of the tensile residual stresses in sheet rolled products with 20-50 mm of thickness reaches 80-65 MPa. As a result of the subsequent technological redistribution, the residual stresses change in magnitude and sign, and reach 0.8-1.2 of the yield strength of the base metal. The most unfavorable from the point of view of the serviceability of OSP are the tensile residual stresses in welded joints, the maximum value of which is 350...500 MPa. High temperature tempering after welding does not always lead to the desired result: in the heat-affected zone of the corner joints of nozzles mounting to the waist tube of the node, the residual stresses amount to 120-150 MPa. Preheating temperatures in the range of 120-1600С do not have a significant effect on the value of residual welding stresses. For more effective reduction of σrs , its value should be 200-4500С, depending on the thickness of the joined parts and the strength class of the steel.

Heat Treatment of Ni-Ti Alloy for Improvement of Shape Memory Effect

1997 ◽  
Vol 12 (1) ◽  
pp. 107-115 ◽  
Author(s):  
K. Sadrnezhaad ◽  
F. Mashhadi ◽  
R. Sharghi
Keyword(s):  
Heat Treatment ◽  
Shape Memory ◽  
Shape Memory Effect ◽  
Memory Effect ◽  
Ti Alloy

The Effect of Heat Treatment on the Shape Memory Effect of Ni-Ti Alloy Ultra-Thin Wires

2011 ◽  
Vol 332-334 ◽  
pp. 912-915
Author(s):  
Dan Zhang ◽  
Lei Xu ◽  
Rui Wang ◽  
Li Feng Xu
Keyword(s):  
Heat Treatment ◽  
Shape Memory Alloy ◽  
Shape Memory ◽  
Shape Memory Effect ◽  
Memory Effect ◽  
Crystal Morphology ◽  
Treatment Temperature ◽  
Ti Alloy ◽  
Thin Wires ◽  
Treatment Conditions

Various heat treatment conditions with temperature scans of 300-700 °C, and annealing time scans of 1-4 hours were adopted in the annealing of Ti-49.5at.%-Ni shape memory alloy ultra thin wires. The mechanical hysteretic curves and the crystal morphology were obtained by the tensile-recovery testing and scan electric microscopes (SEM). The result shows that the shape memory effect of Ni-Ti alloy first decline after rising with the heat treatment temperature increases. Alloy with heat treatment effect in 500°C, presents the best. Time is not a significant factor for heat treatment.

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