scholarly journals Влияние легирующих добавок кобальта и молибдена на структуру и параметры памяти формы пористого реакционно-спеченного никелида титана

Author(s):  
Н.В. Артюхова ◽  
Ю.Ф. Ясенчук ◽  
А.С. Гарин ◽  
В.Э. Гюнтер

AbstractWe have studied the structure and properties of porous nickel titanium (TiNi) alloys obtained upon reaction sintering of Ti and Ni powders with Co and Mo additives. It is established that Co and Mo doping additives retain the compaction of Ni powder achieved at the initial stage of sintering. The maximum deformation of porous samples loaded in the austenite state was observed upon adding Co, while the addition of Mo resulted in minimum deformation. The addition of Co leads to single-stage martensitic transformation in TiNi phase, while the addition of Mo leads to the two-stage transformation that is more homogeneous over the volume. Both Co and Mo additives lead to increase in the maximum accumulated strain due to the formation of favorably oriented stress-induced martensite and reoriented quench-induced martensite.

2014 ◽  
Vol 5 ◽  
pp. 204173141454067 ◽  
Author(s):  
Waldemar Hoffmann ◽  
Therese Bormann ◽  
Antonella Rossi ◽  
Bert Müller ◽  
Ralf Schumacher ◽  
...  

2020 ◽  
Vol 12 (6) ◽  
pp. 168781402092265
Author(s):  
Zhou Wang ◽  
Yin Chen ◽  
Tao Wang ◽  
Bo Zhang

As an important modern weapon, the development of infrared-guided missile reflects comprehensive national strength of a country. Therefore, it is especially important to establish a semi-physical simulation device to test the performance of missile, and the test device requires high accuracy. Based on the above background, an infrared guidance test device is designed in this article. The accuracy of its shell and rotating mechanism are studied in detail, and the error factors are quantified to provide theoretical basis for structural optimization. The orthogonal experiment design reduces the number of sensitivity analysis experiments on key design parameters. Factors affecting the maximum deformation and overall quality of the shell were determined. The range method was used to analyze sensitivity factors, and the final optimization result that met the minimum deformation and minimum quality was determined. Experimental results show that the rotation error of the main shaft of the rotating mechanism includes axial, radial, and angular motion errors, and experimental value is basically consistent with theoretical value. After the shell optimization, the infrared target pointing error [Formula: see text] and the infrared target position offset error ξ′ = 0.1525 mm meet the accuracy requirements. This method can provide new ideas for precision research and optimization of structural design of rotating mechanism.


2020 ◽  
Vol 63 (7) ◽  
pp. 1243-1248
Author(s):  
E. S. Marchenko ◽  
Yu. F. Yasenchuk ◽  
G. A. Baigonakova ◽  
S. V. Gyunter ◽  
A. A. Shishelova

Author(s):  
Wesley A. Salandro ◽  
Joshua J. Jones ◽  
Timothy A. McNeal ◽  
John T. Roth ◽  
Sung-Tae Hong ◽  
...  

Previous studies have shown that the presence of a pulsed electrical current, applied during the deformation process of an aluminum specimen, can significantly improve the formability of the aluminum without heating the metal above its maximum operating temperature range. The research herein extends these findings by examining the effect of electrical pulsing on 5052 and 5083 Aluminum Alloys. Two different parameter sets were used while pulsing three different heat treatments (As Is, 398°C, and 510°C) for each of the two aluminum alloys. For this research, the electrical pulsing is applied to the aluminum while the specimens are deformed, without halting the deformation process. The analysis focuses on establishing the effect the electrical pulsing has on the aluminum alloy’s various heat treatments by examining the displacement of the material throughout the testing region of dogbone shaped specimens. The results from this research show that pulsing significantly increases the maximum achievable elongation of the aluminum (when compared to baseline tests conducted without electrical pulsing). Significantly reducing the engineering flow stress within the material is another beneficial effect produced by electric pulsing. The electrical pulses also cause the aluminum to deform non-uniformly, such that the material exhibits a diffuse neck where the minimum deformation occurs near the ends of the specimen (near the clamps) and the maximum deformation occurs near the center of the specimen (where fracture ultimately occurs). This diffuse necking effect is similar to what can be experienced during superplastic deformation. However, when comparing the presence of a diffuse neck in this research, electrical pulsing does not create as significant of a diffuse neck as superplastic deformation. Electrical pulsing has the potential to be more efficient than traditional methods of incremental forming since the deformation process is never interrupted. Overall, with the greater elongation and lower stress, the aluminum can be deformed quicker, easier, and to a greater extent than is currently possible.


1992 ◽  
Vol 271 ◽  
Author(s):  
Yoshiyuki Yasutomi ◽  
Masahisa Sobue ◽  
Jiro Kondo

ABSTRACTKnowing the nitridation mechanism of Si is important to obtain near-net-shape high strength reaction bonded ceramics. In this report, comparison of nitridation mechanism of small spherical Si powder produced by plasma arc method and large faceted Si powder, is discussed on the basis of microstructural analyses by SEM and TEM. From the analyses, nitrogen diffuses through the oxide film of Si powder and forms Si3N4 under the oxide films during the initial stage of sintering. At higher temperature, the oxide film transform into fine Si3N4 grains when heated to the 1350°C. The Si3N4 has morphology of hollow shell and a size, which corresponds to that of the original Si particles.


Biomaterials ◽  
2005 ◽  
Vol 26 (29) ◽  
pp. 5801-5807 ◽  
Author(s):  
Oleg Prymak ◽  
Denise Bogdanski ◽  
Manfred Köller ◽  
Stefan A. Esenwein ◽  
Gert Muhr ◽  
...  

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