Microstructure and Mechanical Property of MoSi2 Based Composites

2005 ◽  
Vol 475-479 ◽  
pp. 707-710 ◽  
Author(s):  
Sang Ll Lee ◽  
Jin Kyung Lee ◽  
Byeong Hyeon Min ◽  
Yun Seok Shin ◽  
Dong Su Bae ◽  
...  

This study dealt with both the strengthening of matrix and the suppression of interfacial reaction for the development of high toughness Nb/MoSi2 laminate composites. The impact values of Nb/MoSi2, Nb/MoSi2-SiC, Nb/MoSi2-ZrO2 laminate composites were investigated at the room temperature. The flexural strength of MoSi2 based composites containing SiC or ZrO2 particles were also evaluated at elevated temperatures. The reduction of reaction layer by the addition of ZrO2 particles led to the sufficient improvement in the impact value of Nb/MoSi2 laminate composites. The flexural strength of MoSi2-SiC and MoSi2-ZrO2 materials decreased at temperatures higher than 800 °C.

2005 ◽  
Vol 290 ◽  
pp. 344-347
Author(s):  
Miroslav Černý ◽  
D. Bednářová ◽  
Petr Glogar ◽  
Ján Dusza ◽  
Emőke Rudnayová

Mechanical and fracture properties of unidirectional composites reinforced with R-glass fibres and utilizing various commercially available polysiloxane resins as matrix precursors were investigated. As the matrix becomes more brittle after the pyrolysis the impact toughness and flexural strength of the composites fall. On the other hand, the shear modulus rises after the pyrolysis as the matrix becomes stiffer in shear. The appearance of fracture surfaces generated during the flexural strength at room temperature (RT) and elevated temperatures is discussed.


2013 ◽  
Vol 770 ◽  
pp. 308-311 ◽  
Author(s):  
Ming Dong Yi ◽  
Chong Hai Xu ◽  
Zhao Qiang Chen ◽  
Guang Yong Wu

A new nanomicro composite self-lubricating ceramic tool material was prepared with vacuum hot pressing technique. The effect of nanoAl2O3 powders on the microstructure and mechanical properties of nanomicro composite self-lubricating ceramic tool material was investigated. With the increase of nanoAl2O3 content, the hardness and fracture toughness first up then down. When the nanoAl2O3 content is 4 vol.%, the flexural strength, hardness and fracture toughness reaches 562 MPa, 8.46 MPa·m1/2 and 18.95 GPa, respectively. The microstructure and mechanical property of nanomicro composite self-lubricating ceramic tool material can be improved by the grain refinement strengthening of nanoAl2O3.


2008 ◽  
Vol 19 (4) ◽  
pp. 348-353 ◽  
Author(s):  
Rafael Leonardo Xediek Consant ◽  
Erica Brenoe Vieira ◽  
Marcelo Ferraz Mesquita ◽  
Wilson Batista Mendes ◽  
João Neudenir Arioli-Filho

This study evaluated the effect of microwave energy on the hardness, impact strength and flexural strength of the Clássico, Onda-Cryl and QC-20 acrylic resins. Aluminum die were embedded in metallic or plastic flasks with type III dental stone, in accordance with the traditional packing technique. A mixing powder/liquid ratio was used according to the manufacturer's instructions. After polymerization in water batch at 74ºC for 9 h, boiling water for 20 min or microwave energy at 900 W for 10 min, the specimens were deflasked after flask cooling at room temperature, and submitted to finishing. Specimens non-disinfected and disinfected by microwave irradiation were submitted to hardness, impact and flexural strength tests. Each specimen was immersed in distilled water and disinfected in a microwave oven calibrated to 650 W for 3 min. Knoop hardness test was performed with 25 g load for 10 s, impact test was carried out using the Charpy system with 40 kpcm, and 3-point bending test with a crosshead speed of 0.5 mm/min until fracture. Data were submitted to statistical analysis by ANOVA and Tukey's test (?=0.05). Disinfection by microwave energy decreased the hardness of Clássico and Onda-Cryl acrylic resins, but no effect was observed on the impact and flexural strength of all tested resins.


2011 ◽  
Vol 311-313 ◽  
pp. 2251-2254
Author(s):  
Le Ping Bu ◽  
Qing Tai Shen ◽  
Pei Wu

The best is to read these instructions and follow the outline of this text. Mg-RE-B alloy with minuteness particle structure (MPS) were prepared by ingot metallurgy including as-cast and hot-extruded processing, and the microstructure and mechanical property of Mg-6RE-3B2O3 (wt%) alloys were investigated before and after hot-extruded. The Mg-RE-B alloy has satisfied grain size and particle structure, went with excellent mechanical property of tensile yield strength of 520 MPa and elongation of 5% at room temperature. The MPS Mg-RE-B alloy is a promising candidate among lightweight structural materials


Author(s):  
SKM. Pothinathan ◽  
M. Muthukannan ◽  
N. Selvapalam ◽  
S. Christopher Gnanaraj

AbstractIn this study, an endeavor is made to discuss mainly the mechanism, use, and application of polymer modified concrete which is increasing in general fame due to its simplicity, ease of handling, proficiency, and agreeable outcomes. This work explores the impact of adding a new polymer named glycoluril on the mechanical property through the estimation of compression, tension, and flexural strength. Physical properties such as density, sorptivity, and acid resistance were studied to establish the durability of concrete. This examination additionally ponders the impact of polymer in concrete and polymer dosage. Series of concrete mix with 0%, 1%, 2%, 3%, and 4% glycoluril by the mass of binder were prepared, cured, and tested in 7 days and 28 days. Results indicate that there is no adjustment in the workability aspect, however, the improvement of strength factor in compression, tension, and flexure is recorded when compared with the conventional concrete. The experimental results show that by increasing the proportion of glycoluril, the strength of concrete increased up to 3% in addition. In the meantime, the 3% addition provided a higher outcome than the other blend. Further expanding the polymer content marginally decreased the strength. The outcome affirms that the utilization of new polymer in concrete will increase the desired property.


2020 ◽  
Vol 17 (2) ◽  
pp. 42-47
Author(s):  
Patrik Permana Putra Wijaya ◽  
Juliana Anggono

Natural fibers used in the fabrication of biocomposite product can support the need of the industries for lightweight yet strong material. Sugarcane bagasse is one of the available natural fibers in Indonesia. There have been some research done on these bagasse fibers as reinforcement materials for plastics and their incorporation to the matrix has improved its strength. This research aimed to evaluate the fabrication of a car package tray prototype. The composition and the bagasse were prepared in accordance with the previous research in which the bagasse were alkali treated using NaOH solution of 8 wt% for one hour at room temperature. The hotpressed prototype was evaluated by its physical outlook and the mechanical property of its preform. The flexural test shows a low flexural strength of the prototype (7.4 MPa) compared to the required strength of the current material (woodboard) used by the industry (35.58 MPa). The evaluation shows the clustering of bagasse fibers, uneven distribution of sugarcane/PP in the structure and low adhesion at the interfacial region between bagasse fibers and PP.


Metals ◽  
2021 ◽  
Vol 11 (11) ◽  
pp. 1693
Author(s):  
Robin Emmrich ◽  
Ulrich Krupp

The present study aims at the development of precipitation hardening fully ferritic steels with increased aluminum and niobium content for application at elevated temperatures. The first and second material batch were alloyed with tungsten or molybdenum, respectively. To analyze the influence of these elements on the thermally induced precipitation of the intermetallic Fe2Nb Laves phase and thus on the mechanical properties, aging treatments with varying temperature and holding time are performed followed by X-ray diffraction (XRD) analysis and scanning electron microscopy (SEM) including elemental contrast based particle analysis as well as hardness measurements and tensile tests at room temperature and at 500 °C. The incorporation of molybdenum into the Laves phase sets in at an earlier stage of aging than the incorporation of tungsten, which leads to faster growth and coarsening of the Laves phase in the molybdenum-alloyed steel. Nevertheless, both concepts show a fast and massive increase in hardness (280 HV10) due to precipitation of Laves phase during aging at 650 °C. After 4 h aging, the yield strength increase at room temperature is 100 MPa, which stays stable at operation temperatures up to 500 °C.


2022 ◽  
Vol 961 (1) ◽  
pp. 012085
Author(s):  
Aseel Mansi ◽  
Nadhim Hamah Sor ◽  
Nahla Hilal ◽  
Shaker M A Qaidi

Abstract The use of nano clay to improve the qualities of construction materials and engineering applications has attracted a lot of discussion in recent years. This review article summarizes the influence of nano clay as a cement substitute and supplement on the performance of conventional and high-performance concrete. The addition of nano clay to high performance concrete revealed an increase in compressive and flexural strength, as well as durability attributes such as resistance to elevated temperatures and sulfate attack, while simultaneously decreasing porosity, permeability, and water absorption. This enhancement is a result of nano clay’s roles as nano reinforcements, nanofillers, nucleation sites, and reactive pozzolans, which promote hydration and increase material characteristics.


Aerospace ◽  
2020 ◽  
Vol 7 (3) ◽  
pp. 28
Author(s):  
Md.Zahid Hasan

Many high-strength composite materials have been developed for aircraft structures. GLAss fiber REinforced aluminum (GLARE) is one of the high-performance composites. The review of articles, however, yielded no study on the impact damage of heated GLARE laminates. This study, therefore, aimed at developing a numerical model that can delineate the continuum damage of GLARE 5A-3/2-0.3 laminates at elevated temperatures. In the first stage, the inter-laminar interface failure of heated GLARE laminate had been investigated at room temperature and 80 °C. The numerical analysis employed a three-dimensional GLARE 5A-3/2-0.3 model that accommodated volumetric cohesive interfaces between mating material layers. Lagrangian smoothed particles populated the projectile. The model considered the degradation of tensile and shear modulus of glass fiber reinforced epoxy (GF/EP) at 80 °C, while incorporated temperature-dependent critical strain energy release rate of cohesive interfaces. When coupled with the material particulars, an 82 m/s bird impact at room temperature exhibited delamination first in the GF/EP 90°/0° interface farthest from the impacted side. Keeping the impact velocity, interface failure propagated at a slower rate at 80 °C than that at room temperature, which was in agreement with the impact damage determined in the experiments. The outcomes of this study will help optimize a GLARE laminate based on the anti-icing temperature of aircraft.


DYNA ◽  
2015 ◽  
Vol 82 (193) ◽  
pp. 137-144
Author(s):  
Yisel Larrua Pardo ◽  
Rafael Larrua Quevedo ◽  
Valdir Pignatta Silva

In this paper the thermal analysis of the push out test of steel – concrete channel connections at elevated temperatures is carried out. The study takes into account numeric results generated by the program SuperTempcalc for two alternatives: protected and unprotected beams. Temperatures are proposed to be considered in determining the reduction factors of resistance and the impact of these results in determining the strength of the connection is evaluated. Finally, a simplified method for calculating the resistance of the connection is proposed, which considers defined temperatures in the concrete by the thermal analysis and is consistent with the formulations for calculating the resistance of channel connections at room temperature and with the current formulation for stud connections at elevated temperatures provided by international codes.


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