Physical and Mechanical Properties of Mo5X3+α (X=Si, B, C) Single Crystals

2002 ◽  
Vol 753 ◽  
Author(s):  
Taisuke Hayashi ◽  
Kazuhiro Ito ◽  
Katsushi Tanaka ◽  
Masaharu Yamaguchi

ABSTRACTMo5X3+α (X=Si, B, C) intermetallic compounds such as Mo5SiB2 (D8l), Mo5Si3 (D8m) and Mo5Si3C (D88) have a great potential for ultra-high temperature applications. The present study was undertaken putting greater emphasis on clarifying how their physical and mechanical properties are similar or different in terms of a structure type. Some interesting features are summarized in this paper.The resistivity of Mo5SiB2, Mo5Si3 and Mo5Si3C single crystals exhibited a negative curvature (d2ρ(T)/dT2<0), with a tendency towards saturation. In the Mo5Si3C with large ρ0 due to impurity carbon atoms, resistivity saturation is pronounced. In contrast, a much higher temperature is required to reach saturation in the Mo5SiB2. The anisotropy ratio of CTE (αc/αa) for the Mo5SiB2 is about 1.2–1.6 and is significantly reduced from about 2 of the Mo5Si3 and Mo5Si3C. On the other hand, the Young's modulus of the Mo5SiB2 is more anisotropic than those of the Mo5Si3 and Mo5Si3C. Plastic anisotropy was observed in the Mo5SiB2, because only slip on [001] {100} is operative at 1500°C. On the contrary, plastic deformation was observed at temperatures above 1300°C for the Mo5Si3C and Mo5Si3. Anisotropy of their plastic deformation was much less than that of the Mo5SiB2, presumably because more than two slip systems can be activated. Creep resistance of the Mo5SiB2 is much better than that of the Mo5Si3 as well as the most advanced materials such as MoSi2 and Si3N4 based structural ceramics.

Author(s):  
Georg Frommeyer ◽  
Sven Knippscheer

Aluminum-rich intermetallic compounds of the Al3X-type with transmission metals (X = Ti. Zr, Nb, V) of Groups IVb and Vb are of interest in the development of novel high-temperature and lightweight structural materials. This article describes the important physical and mechanical properties of trialuminides with DO22 structure and their L12 variations. Topical coverage includes: crystal structure and selected physical properties, plastic deformation, oxidation behavior, and applications.


2012 ◽  
Vol 627 ◽  
pp. 85-89 ◽  
Author(s):  
Hai Xia Zhang ◽  
Xi Chang Zhang

To analyze the structure and performance of Outlast acrylic fiber, the fiber structure was observed respectively by FTIR spectra, X-ray diffraction and scanning electron microscope, the normal physical and mechanical properties were measured, and the thermo-regulated performance was investigated by differential scanning calorimeter, thermal gravimeter analysis and step cooling test. The results indicate that the structure and normal physical and mechanical properties of Outlast acrylic fiber are slightly different from that of normal acrylic fiber. Both the melting peak and crystallization peak of Outlast acrylic fiber are single peaks, and the phase change temperature range is applicable and the phase change enthalpy is high. The decomposition temperature of Outlast acrylic fiber is around 311.85°C. The cooling velocity of Outlast acrylic fiber decreases exponentially with the increase in time, and the thermo-regulated ability of Outlast acrylic fiber is better than that of normal acrylic fiber.


2009 ◽  
Vol 79-82 ◽  
pp. 1687-1690
Author(s):  
Xing Min Cao ◽  
Yu Bin Zhu ◽  
Fuan Guo ◽  
Chao Jian Xiang

Electrical conductivity, tensile strength and micro-hardness of Cu-3.5wt.%Ti-0.1wt.%Zr-RE alloy were investigated after optimizing technics of plastic deformation and the heat treatment. The results show that good combination of the physical and mechanical properties, such as tensile strength 1160 MPa, micro-hardness 335 Hv and electrical conductivity 15 IACS% can be obtained on peak aging at 420°C for 7 h. Maximum strength was associated with the precipitation of metastable, ordered and coherent β/ (Cu4Ti) phase on peak aging. Then the strength decreased due to the precipitation of β (Cu3Ti) phase in alloys overaged.


2014 ◽  
Vol 783-786 ◽  
pp. 443-448 ◽  
Author(s):  
Bartłomiej Płonka ◽  
Krzysztof Remsak ◽  
Marek Nowak ◽  
Marzena Lech-Grega ◽  
Piotr Korczak

The object of this study was to develop parameters of plastic deformation in hot direct extrusion and die forging process of magnesium alloy MgAlZn. Extrusion process was conducted in the temperature range 350°C÷450°C at different extrusion speeds (ram speed 0.5 mm/s÷3 mm/s). The extrusion tests have showed that for this alloy it is possible to use the temperature of the extruded material ranging from 350°C÷450°C when the process is run at the optimum ram speed. Higher temperature of extrusion is beneficial For higher ram speed of 3mm/s, in this alloy at a temperature of 420÷450°C, cracks began to show in the surface. The same problem were for die forging. Extruded rods and forging parts were characterized by mechanical properties and structure in different heat treatment tempers. This magnesium alloy obtained in the T5 temper higher mechanical properties then T6 temper. The paper also presents research results of investigation of conversion coating on MgAlZn magnesium alloy by anodic oxidation method in non-chromium solutions. It was found that the coating produced in non-chromium solutions show considerable increase of corrosion resistance of tested alloy.Keywords: Mg alloys, extrusion, mechanical properties, structure, corrosion resistance.


2017 ◽  
Vol 743 ◽  
pp. 203-206 ◽  
Author(s):  
Alexander A. Kozulin ◽  
Vladimir A. Krasnoveikin ◽  
Vladimir A. Skripnyak ◽  
Evgeny N. Moskvichev ◽  
Valery E. Rubtsov

This study examines the effect of severe plastic deformation on the physical and mechanical properties of a light structural Al-Mg alloy. Severe plastic deformation has been performed by equal channel angular pressing through a die with an angle of 90° between the channels to produce ultrafine-grained structure in specimens of studied alloy. A complex investigation of the physical and mechanical properties of the processed alloy has been carried out to examine the microstructure and texture, and to measure microhardness, yield stress and ultimate tensile strength. The obtained results demonstrate high efficiency of the chosen treatment method and mode of producing a light ultrafine-grained alloy.


2001 ◽  
Vol 9 (7) ◽  
pp. 591-602 ◽  
Author(s):  
K Ito ◽  
K Ihara ◽  
K Tanaka ◽  
M Fujikura ◽  
M Yamaguchi

Author(s):  
Oleksandr Babachenko ◽  
Ganna Kononenko ◽  
Katerina Domina ◽  
Rostislav Podolskyi ◽  
Olena Safronova

A review of research in the field of modeling experiments on heat treatment and pressure treatment of metal and the impact on the physical and mechanical properties of steel with a chemical composition of 0.59% C, 0.31% Si, 0.73% Mn. A mathematical model for calculating the physical and mechanical properties of steel in the process of hot plastic deformation has been developed and prospects for further development of research in this area have been identified. As a result of modeling, the following functions were obtained: the amount of deformation in the direction of the applied force divided by the initial length of the material. The coefficient of elongation of the material with the actual chemical composition at a temperature of 1250 ± 10 ° C, which was 0.32. When comparing the values of the load that was applied to the GPA in the laboratory and the results of calculations using the developed model, it was found that they have close values of about 45 MPa. This confirms the adequacy of the obtained model.A review of research in the field of modeling experiments on heat treatment and pressure treatment of metal and the impact on the physical and mechanical properties of steel with a chemical composition of 0.59% C, 0.31% Si, 0.73% Mn. A mathematical model for calculating the physical and mechanical properties of steel in the process of hot plastic deformation has been developed and prospects for further development of research in this area have been identified. As a result of modeling, the following functions were obtained: the amount of deformation in the direction of the applied force divided by the initial length of the material. The coefficient of elongation of the material with the actual chemical composition at a temperature of 1250 ± 10 ° C, which was 0.32. When comparing the values of the load that was applied to the GPA in the laboratory and the results of calculations using the developed model, it was found that they have close values of about 45 MPa. This confirms the adequacy of the obtained model.


Author(s):  
Dmytro Pavlenko ◽  
Yaroslav Dvirnyk ◽  
Radoslaw Przysowa

BACKGROUND: Manufacturing costs, along with operational performance, are among the major factors determining the selection of the propulsion system for unmanned aerial vehicles (UAVs), especially for aerial targets and cruise missiles. OBJECTIVES: In this paper, the design requirements and operating parameters of small turbofan engines for single-use and reusable UAVs are analysed to introduce alternative materials and technologies for manufacturing their compressor blades, such as sintered titanium, a new generation of aluminium and an alloy based on titanium aluminides. METHODS: To assess the influence of severe plastic deformation (SPD) on the hardening efficiency of the proposed materials, the alloys in the coarse-grained and submicrocrystalline states were studied. Changes in physical and mechanical properties of materials were taken into account. The thermodynamic analysis of the compressor was performed in a finite element analysis system (ANSYS) to determine the impact of gas pressure and temperature on the aerodynamic surfaces of compressor blades of all stages. RESULTS: Based on thermal and structural analysis, the stress and temperature maps on compressor blades and vanes were obtained, taking into account the physical and mechanical properties of advanced materials and technologies of their processing. The safety factors of the components were established based on the assessment of their stress-strength reliability. Thanks to nomograms, the possibility of using the new materials and the technologies was confirmed in view of the permissible operating temperature and safety factors of blades. CONCLUSIONS: The proposed alternative materials and production technologies for the compressor blades and vanes meet the design requirements of the turbofan at lower manufacturing costs.


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