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Go to Editorial ManagerMost of building rubbles or wastes contain some damaged materials such as cement, brick, steel, ceramic, plastic and other substances. Among these materials, ceramic and brick when using both of them as a partial replacement by the weight of conventional coarse aggregate in mixture concrete with presence of variety ratios ( 10% to 30%) for sawdust as replacement of fine aggregate, the resulting concrete properties will affected. So, this paper was based on the study some properties of concrete that produced of 50% replacement for those rubbles plus to presence 10%, 20% and 30% sawdust for both of them. The results revealed that present of sawdust with each of type of those rubbles provides database which are potential to be used in the production of lighter and economical new concrete material. Furthermore, the higher ratios of sawdust (more than 10 %) lead to obvious affected on the strength as well as other properties. While, those negative effects will perceptible improved when added 10% sawdust in ceramic aggregate concrete compared to brick aggregate concrete.
The study here under describes the impact of adding a nano-scaled ceramic particles on the mechanical and fatigue behaviors of aluminum matrix composites AMCs containing 0.5 ,1.0 ,1.5, and 2 % wt. of nano-scaled B4C and Al2O3 particles were dispersed in molten aluminum by the stir-casting process. Vickers, tensile, and fatigue devices were utilized to evaluate the mechanical behavior of composites in the fabrication process. The results show that increasing the weight percentage of nano-ceramic particles increased the hardness, maximum tensile stress, and fatigue strengths of the base alloy. Furthermore, all of the above behaviors of AMCs reinforced with B4C particles are better than those of AMCs reinforced with Al2O3 particles.
In this research, polymer polymethyl methacrylate PMMA composite with nano ceramic Zr and HAp material were used to manufacture one part of the implant system (femoral ball head of hip implant). Three set of hybrid materials were fabricated and tested for this study; the first mixtures which contains 100% (PMMA), the second mixtures which contains (90% (PMMA) + 8% (Zr) + 2% (HAp)), and the third mixtures which contains (80% (PMMA) + 18% (Zr) + 2% (HAp)) were investigated. The mechanical properties for these mixtures increased with the increasing of nano ceramic concentration (Zr and HAp) composite material in the polymer compared to pure polymer PMMA sample. However, an increase in the concentration of Zr from 8% to 18% content cause a considerable decrease of the hardness where a drop of homogeneity in Zr- matrix PMMA contact occurred, V Hardness value are (68 ,80 and 70) Kg.mm for three mixture respectively. The wear test was in agreement with results of the hardness test. The weight loss of the above samples of the wear test were (0.041, 0.035 and 0.037) respectively. According to mechanical properties, the best sample contains (90% (PMMA) + 8% (Zr) + 2% (HAp)). The Scanning electron microscopy resolute showed the particles forming semi-continuous network along grain boundaries polymer for second sample mixtures containing (90% (PMMA) + 8% (Zr) + 2% (HAp)), provides a low atomic packing and high energy. This will make the grain boundaries more reactive and strengthen mechanical performance. The Optical microscopy, Scanning electron microscopy and Xray spectroscopy analysis for In vitro test using SBF shows the growth of HAp layer with an increase in concentration of Ca and P elements formed on the surface of the second sample. This display of good results is a proof of the biocompatibility of the polymer sample.
Al2O3 is a major reinforcement in aluminum-based composites, which have been developing rapidly in recent years. The aim of this paper is to investigate the effect of alumina phases and amounts on the physical properties of fabricated Al-Al2O3 composite. Alpha micro and gamma nano of alumina with particle size of 30µm and 20 nm respectively reinforced aluminum matrix of 45 µm. The percentage of reinforcement material were in the range of (5, 10 and 15wt.%) fabricated by powder metallurgy technique. Specimens dimensions were a disc specimens with 11mm diameter and 5 mm thickness. The green density was achieved under compaction pressure of 500MPa, and then sintered under pressure less sintering at 500ºC in a vacuumed tube furnace for two hours Physical properties of the composite samples have been studied such as relative density, sintered density, porosity, microstructure characteristics, particles distribution, agglomeration, grain sizes and granularity accumulation distribution. It has been noticed that at the micro alumina phase, its relative densities are decreased when there is an increase in amount of micro alumina addition, on the contrary in case of nano composites, where the relative density are increasing along with the increase in nano alumina addition. At micro and nano composites, the produced relative densities are less than the pure aluminum relative density. Agglomeration are increasing with the increase in amount of reinforcement, while its more obvious with nano composite. Grain size reduced with the increase in amount of alumina in micro and nano composites, while, the obtained average grain size diameter is less in nano composite than in micro composites. It is obvious from the results that the variation in physical properties and microstructure of Al-Al2O3 composite are depends on both of alumina phases (size) and percentages. At 15wt.% of nano alumina higher relative density and lower porosity will be obtained.
The traditional finishing method cannot keep up with recent labor market requirements, solve the problem of increasing production, improve the surface roughness and accuracy of workpiece. While the unconventional magnetic abrasive finishing (MAF) method has shown as a promising technique that can be used to finish complicated surfaces. MAF finishes metals, alloy, ceramic, and other materials that are difficult to finish by other processes. In another word, MAF improves the quality of surfaces with low cost._x000D_ This paper focuses on optimize and study the effect of inductor and pole geometry (radius of hole, angle of core, angle of pole, radius of pole), on (surface roughness (Ra) and material removal weight (W)) and fined the optimum values that increase the efficiency of MAF method. Taguchi method employed to study the influence of geometry parameters and find the optimum values using orthogonal array L9. The results conclude that the most significant factor that effects change in surface roughness (?Ra) and material removal weight(?W) are radius of the hole (R) and angle of core (?), respectively.