Distinct heat treatments and powder size ratios affecting mechanical responses of Al/Si/Cu composites

2021 ◽  
pp. 002199832110293
Author(s):  
Luz M Satizabal ◽  
Heloisa FN Caurin ◽  
Yuri A Meyer ◽  
Giovana S Padilha ◽  
Ausdinir D Bortolozo ◽  
...  

The aim in this investigation is focused on the evaluation of two distinctive powder size ratios of pure elements (Al, Si and Cu) powders. Heat treatments (T4 and T6) affecting the mechanical strengths of Al/Si/Cu composites are also investigated. The novelty concerns to pure elements to constituting the composites and no melting or stir casting route are used. It is found that the densifications and tensile strengths are similar when distinct powder size ratios are used. It is also found that T4 and T6 treatments increases and decreases the mechanical strengths, respectively. The Si content indicates a deleterious effect in mechanical behavior. The T6 aging provides θ-Al2Cu incoherent with Al matrix, and the compressive strength is decreased. This suggests that the examined Al/Cu composites (using pure powders) are potential materials considering economical and environmentally friendly aspects.

2018 ◽  
Vol 5 (13) ◽  
pp. 26873-26877 ◽  
Author(s):  
V. Mohanavel ◽  
S. Suresh Kumar ◽  
K. Mariyappan ◽  
P. Ganeshan ◽  
T. Adithiyaa

2020 ◽  
Vol 108 (2) ◽  
pp. 203
Author(s):  
Samia Djadouf ◽  
Nasser Chelouah ◽  
Abdelkader Tahakourt

Sustainable development and environmental challenges incite to valorize local materials such as agricultural waste. In this context, a new ecological compressed earth blocks (CEBS) with addition of ground olive stone (GOS) was proposed. The GOS is added as partial clay replacement in different proportions. The main objective of this paper is to study the effect of GOS levels on the thermal properties and mechanical behavior of CEB. We proceeded to determining the optimal water content and equivalent wet density by compaction using a hydraulic press, at a pressure of 10 MPa. The maximum compressive strength is reached at 15% of the GOS. This percentage increases the mechanical properties by 19.66%, and decreases the thermal conductivity by 37.63%. These results are due to the optimal water responsible for the consolidation and compactness of the clay matrix. The substitution up to 30% of GOS shows a decrease of compressive strength and thermal conductivity by about 38.38% and 50.64% respectively. The decrease in dry density and thermal conductivity is related to the content of GOS, which is composed of organic and porous fibers. The GOS seems promising for improving the thermo-mechanical characteristics of CEB and which can also be used as reinforcement in CEBS.


Author(s):  
Benedikt Diepold ◽  
Mathias Sebastian Palm ◽  
Andreas Wimmer ◽  
Torsten Sebald ◽  
Heinz Werner Höppel ◽  
...  

2021 ◽  
Vol 11 (22) ◽  
pp. 10653
Author(s):  
Jingwei Gao ◽  
Chao Xu ◽  
Yan Xi ◽  
Lifeng Fan

This study investigated the effects of freezing temperature under freeze-thaw cycling conditions on the mechanical behavior of sandstone. First, the sandstone specimens were subjected to 10-time freeze-thaw cycling treatments at different freezing temperatures (−20, −40, −50, and −60 °C). Subsequently, a series of density, ultrasonic wave, and static and dynamic mechanical behavior tests were carried out. Finally, the effects of freezing temperature on the density, P-wave velocity, stress–strain curves, static and dynamic uniaxial compressive strength, static elastic modulus, and dynamic energy absorption of sandstone were discussed. The results show that the density slightly decreases as temperature decreases, approximately by 1.0% at −60 °C compared with that at 20 °C. The P-wave velocity, static and dynamic uniaxial compressive strength, static elastic modulus, and dynamic energy absorption obviously decrease. As freezing temperature decreases from 20 to −60 °C, the static uniaxial compressive strength, static elastic modulus, dynamic strength, and dynamic energy absorption of sandstone decrease by 16.8%, 21.2%, 30.8%, and 30.7%, respectively. The dynamic mechanical behavior is more sensitive to the freezing temperature during freeze-thawing cycling compared with the static mechanical behavior. In addition, a higher strain rate can induce a higher dynamic strength and energy absorption.


2018 ◽  
Vol 7 (1) ◽  
pp. 32-43
Author(s):  
Olawale Monsur Sanusi ◽  
M Dauda ◽  
Malachy Sumaila ◽  
Abdulkarim S Ahmed ◽  
M T Isa ◽  
...  

The research aims to study and optimize the formulation of materials required for advanced ceramic production using response surface methodology (RSM). In this research effort, the five (5) process independent variables studied with their corresponding levels are: Antang corundum powder, A (92.2 – 100 %W); polyvinyl alcohol, B (0 – 5 %W); CaO, C (0 – 2.3 %W); MgO, D (0 – 0.5 %W); and the sintering temperature, E (1200 – 1500 °C). The mechanical property responses determined were density, ρ, compressive strength, C/S, flexural strength, F/S; which are key characteristics of ceramics for armour applications. The optimized density, compressive strength and flexural strength of the sintered Antang corundum are 3.45 g/cm3 g, 1982 MPa and 295 MPa respectively; while the respective RSM prediction values are 3.45 g/cm3 g, 1982 MPa and 295 MPa. On comparing the determined optimum mechanical responses of the sintered Antang ceramic with the maximum RSM prediction values, there is high level of assurance in using RSM for the formulation process in ceramic armour development.


2011 ◽  
Vol 462-463 ◽  
pp. 1-6 ◽  
Author(s):  
Tao Suo ◽  
Yu Long Li ◽  
Ming Shuang Liu

As Carbon-fiber-reinforced SiC-matrix (C/SiC) composites are widely used in high-temperature structural applications, its mechanical behavior at high temperature is important for the reliability of structures. In this paper, mechanical behavior of a kind of 2D C/SiC composite was investigated at temperatures ranging from room temperature (20C) to 600C under quasi-static and dynamic uniaxial compression. The results show the composite has excellent high temperature mechanical properties at the tested temperature range. Catastrophic brittle failure is not observed for the specimens tested at different strain rates. The compressive strength of the composite deceases only 10% at 600C if compared with that at room temperature. It is proposed that the decrease of compressive strength of the 2D C/SiC composite at high temperature is influenced mainly by release of thermal residual stresses in the reinforced carbon fiber and silicon carbon matrix and oxidation of the composite in high temperature atmosphere.


2021 ◽  
Vol 16 (3) ◽  
pp. 112-123
Author(s):  
Mahmut Can Şenel ◽  
Mevlüt Gürbüz

In the current work, nano boron nitride (BN) reinforced aluminum (Al) matrix composites with different BN amounts (0.5-2wt.%) were produced by the powder metallurgy(PM) route. This fabrication method consists of dispersing, filtering, mixing, drying, compaction, and sintering processes. The density, compressive strength, micro Vickers hardness, microstructure, and phase structures of Al-BN composites and pure Al were examined. The obtained results indicated that minimum porosity (3.2%), highest density (~2.61g/cm3), Vickers hardness (~50HV), and compressive strength (~168MPa) were obtained at 1%BN reinforced aluminum matrix composite. A tremendous enhancement in Vickers hardness and compressive strength of %1BN reinforced Al matrix composite was achieved as ~61% and ~110% compared to pure Al. Consequently, the mechanical strength of BN reinforced Al-based composites enhanced up to 1% nano boron nitride amount. Due to the clumping of BN nanoparticles, the mechanical strength decreased after this content.


2019 ◽  
Vol 2019 ◽  
pp. 1-10 ◽  
Author(s):  
Xiangfeng Lv ◽  
Xiaohui Yang ◽  
Hongyuan Zhou ◽  
Shuo Zhang

In this study, the specimens of cemented sand were prepared by reinforcing it separately with different contents (0.5%, 1.0%, 1.5%, and 2.0%) of three different polymer fibers (polyamide, polyester, and polypropylene) prepared as filaments of different lengths (6, 9, and 12 mm). Then, these specimens were tested, and the improvement effects of the three fibers on the engineering-mechanical behavior of the cemented sand were analyzed and compared. The different microstructures and chemical compositions of the fiber-reinforced cemented sand specimens were investigated using electron microscopy and X-ray diffraction. Compression tests were performed to obtain the stress-strain curves of the specimens. Comparative analysis was performed on the variation patterns of the mechanical parameters (such as unconfined compressive strength and peak strain) of the specimens. Quantitative analysis was performed on the effect of fiber content and fiber filament length on the failure mode of the specimens. It was shown that the inclusion of fibers led to a change from brittle failure to ductile failure. The macro- and microexperimental results revealed that polypropylene fiber had the best improvement effect on the mechanical behavior of the cemented sand, followed by polyester fiber and polyamide fiber. In particular, the cemented sand specimen reinforced with 1.5% polypropylene fiber prepared as 9 mm length filaments had a brittleness index of 0.0578, exhibited ductile failure (in contrast to the brittle failure of the nonreinforced cemented sand), and yielded the highest unconfined compressive strength and shear strength among the specimens.


Materials ◽  
2019 ◽  
Vol 12 (21) ◽  
pp. 3512 ◽  
Author(s):  
Espedito Felipe Teixeira de Carvalho ◽  
João Trajano da Silva Neto ◽  
Paulo Roberto Ribeiro Soares Junior ◽  
Priscila de Souza Maciel ◽  
Helder Luis Fransozo ◽  
...  

This work reports the main conclusions of a study on the mechanical behavior of concrete under ISO 834 fire with different cooling methods. The aim of this research was to provide reliable data for the analysis of structures damaged by fire. The experimental program used cylindrical concrete test specimens subjected to ISO 834 heating in a furnace up to maximum gas temperatures of 400, 500, 600, 700, and 800 °C. The compressive strength was measured in three situations: (a) at the different temperature levels reached in the furnace; (b) after a natural cooling process; and (c) after aspersion with water at ambient temperature. The results indicate that the concrete residual compressive strength is fairly dependent on the maximum temperature reached in the furnace and revealed that concrete of a lower strength preserved relatively higher levels of strength. The cooling method significantly influenced the strength, albeit at a lower intensity. In all cases, the residual strength remained in the range of 38% to 67% of the strength at ambient temperature. The statistical analysis showed that the data obtained by the experimental program are significant and confirmed the influence of the conditions imposed on the residual strength.


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