Print ISSN: 1681-6900

Online ISSN: 2412-0758

Keywords : Microstructure

Effect of Sodium Chloride on Microstructure and Mechanical Properties of Al-Si alloy

Jafer T. Al-Haidary; Mahdie Mutier Hanon; Yasir Muhi Abdulsahib

Engineering and Technology Journal, 2015, Volume 33, Issue 9, Pages 2187-2197

In this work, the effect of sodium chloride (NaCl) powder addition with different amounts on microstructure and mechanical properties of Al-12 wt. %Si alloy was investigated. In this technique, modification by NaCl was used because of its availability and low price comparing to other modifiers such as Sr and Sb. A 1000 °C as pouring temperature of molten alloy was used. The present results showed that there is a significant change in the mechanical properties and microstructure compared with unmodified alloy. The optimum properties were found by adding 0.5wt% NaCl to the alloy, and also the modification of microstructure alloy. Mechanical properties and microstructure of Al-12wt. %Si alloys that poured from 1000 °C with NaCl additives were compared with the corresponding alloys but at 800 °C pouring temperature, it is found that alloys poured from 1000 °C have best properties as compared with the same alloys poured from 800 °C.

SEM-Backscattered Imaging analysis of Cementitious Composite Matrix Incorporating Mineral Admixture

Maan S. Hassan

Engineering and Technology Journal, 2014, Volume 32, Issue 4, Pages 696-703

Microstructure imaging interpretation of polished surface has become well established as a method for the study of cement and concrete microstructure. This paper is an attempt to provide micro-level examination to the microstructure of cement paste in concrete particularly the hydrated mineral admixture and interfacial transition zone, which received increasing attention due to their effect on the hardened concrete properties. Furthermore, illustrations are provided of the transition area of cement paste adjacent to the aggregate border as well as other cement paste areas. SEM images reveal that pozzolanic reaction is not the only benefit of using mineral admixture. Spherical shape of grains is important to improve the microstructure of cement paste particularly in the interfacial transition zone.

Corrosion Resistance of Aluminum Alloy 7020-T6 in Sea Water

Mustafa Khaleel Ismael

Engineering and Technology Journal, 2011, Volume 29, Issue 8, Pages 1482-1490

The present work is aimed to investigate the effect of heat treatment on corrosion resistance of Al-alloy 7020-T6 in sea water, the specimens which manufactured by (1.5*1.5*0.2) cm, according to ASTM (G31-72) [1] The heat treatment was carried out at 480°C and water quench after that artificial aging are implemented at temperature 150°C for (1, 4) hours. Microstructure and phase properties after heat treatment and corrosion test were investigated by optical microscope; X-ray diffraction and
computer potentiodynamic polarization technique have been used to study corrosion behavior in 3.5% NaCl. The results of corrosion resistance 7020-T6 decrease by solution heat treatment and, increase the holding time from 1- 4 hour would increase the corrosion rate, Intermetallics compounds containing zinc represent as the sacrificial anode and control pitting corrosion in 7020-T6 alloy also, the artificial
ageing time increase the precipitation of zinc and decrease pitting corrosion at 1 hour.

One Parameter Composite Semigroups of Linear Bounded Operators in Strong Operator Topology of Schatten Class Cp

Samir Kasim Hassan; Al-Taie M; Al-Malki Anam; Al-Attar Abeer; Mustafa Khaleel Ismael; Fatema Ahmed Sadeq; Radhi A .Zboon; Jehad R.Kider; Samir K .Hassan; Hussain J. M. Alalkawi; Raad H. Majid; Rawaa A. Alomairy; Luma Abdul Ghani Zghair; Hadia Kadhim J.Al-Ogili; Assifa M. Mohamad; Abbas Sheyaa Alwan; Haider L. Aneed; Assim H Yousif; Salema Sultan Salman; Abbas Hussien Miry; Abduladhem A.Ali; Mohammed Zeki Al-Faiz; Sabah N. mahmood; Khansaa Dawood Selman; Shaymaa Tareq Kadhim

Engineering and Technology Journal, 2011, Volume 29, Issue 8, Pages 1463-1470

For semigroups of linear bounded operators on Hilbert spaces, the problem of
being in Cp , 0 Keywords

Microstructure and Wear Rate of Yttria Reinforced Aluminum – Silicon Matrix Composites

Engineering and Technology Journal, 2010, Volume 28, Issue 23, Pages 1184-1195

In this research, composite materials of hypereutectic aluminum – silicon as a matrix reinforced with different volume fractions (2%, 4%, 6%, 8%) of Yttria particles with grain size between (50 - 75 μm) are prepared. The composites are prepared by vortex technique in which the particles were added to the melt then mixing it by mechanical stirrer then the mixture is poured in a metallic cylindrical molds. After that, the microstructure, Vickers hardness and wear rate were conducted. The results showed the existence of the reinforcement particles in
different amounts in the microstructure and an increase in the hardness for the prepared composites when compared with the unreinforced alloy. The results also showed a better particles distribution and higher hardness with increasing yttria volume fraction. The wear rate of the composites is reduced when compared with the unreinforced alloy due to the hardness increase. More reduction in wear rate was noticed with increasing the Yttria volume fraction, and the better added percent was (8%Y2O3).

Microstructural Modification of Al-base Composite by Friction Stir Processing

Nawal Ezzat

Engineering and Technology Journal, 2010, Volume 28, Issue 6, Pages 1094-1105

A novel surface modifying technique, Friction Stir Processing, is used to
enhance mechanical properties of Al-Si / Al2O3 composite, through micro
structural refinement and homogenization. The effect of processing parameters on
resultant microstructure and wear rate is investigated in this work.
The Friction Stir Processing resulted in significant breakup of the coarse Si
and Al-dendrites and uniform distribution of Si and Al2O3 in the matrix with
significant micro structural refinement. These microstructures changes lead to
significant improvement in wear resistance of composite