Abbas Zarei-Hanzaki

Bio: Abbas Zarei-Hanzaki is an academic researcher from University of Tehran. The author has contributed to research in topics: Microstructure & Dynamic recrystallization. The author has an hindex of 32, co-authored 168 publications receiving 4022 citations. Previous affiliations of Abbas Zarei-Hanzaki include University College of Engineering.

Microstructures and mechanical properties of Al/Al2O3 surface nano-composite layer produced by friction stir processing

Abstract: In this study, a new processing technique, friction stir processing (FSP) was attempted to incorporate nano-sized Al 2 O 3 into 6082 aluminum alloy to form particulate composite surface layer. Samples were subjected to various numbers of FSP passes from one to four, with and without Al 2 O 3 powder. Microstructural observations were carried out by employing optical and scanning electron microscopy (SEM) of the cross sections both parallel and perpendicular to the tool traverse direction. Mechanical properties include microhardness and wear resistance, were evaluated in detail. The results show that the increasing in number of FSP passes causes a more uniform in distribution of nano-sized alumina particles. The microhardness of the surface improves by three times as compared to that of the as-received Al alloy. A significant improvement in wear resistance in the nano-composite surfaced Al is observed as compared to the as-received Al.

Dynamic recrystallization in AZ31 magnesium alloy

Abstract: The effects of temperature and strain rate, as the most important thermomechanical processing (TMP) parameters, on the microstructural evolution of AZ31 magnesium alloy were studied. This was performed applying hot compression tests at a temperature range of 250–450 °C with various strain rates. The results indicated that the amount and the size of dynamically recrystallized grains are increased as Zener–Hollomon parameter decreased. In addition, the evolution of dynamically recrystallized grains was examined with increasing strain. In general, the amount of dynamically recrystallized grain is observed to increase with strain in a sigmoidal form. However, the related grain size was remained constant as strain increased.

The flow behavior modeling of cast A356 aluminum alloy at elevated temperatures considering the effect of strain

Abstract: The flow stress behavior of cast A356 aluminum alloy has been studied by a set of isothermal hot compression tests. The compression tests were carried out in the temperature range of 400–540 °C and strain rates of 0.001, 0.01 and 0.1 s −1 up to a true strain of 0.6. The effects of temperature and strain rate on deformation behavior were represented by Zener–Hollomon parameter in an exponent type equation. Employing an Arrhenius-type constitutive equation, the influence of strain has been incorporated by considering the related materials’ constants as functions of strain. The accuracy of the developed constitutive equations has been evaluated using standard statistical parameters such as correlation coefficient and average absolute relative error. The results indicate that the strain-dependent constitutive equation can lead to a good agreement between the calculated and measured flow stresses in the relevant temperature range.

Review: friction stir welding tools

Abstract: Friction stir welding (FSW) is a widely used solid state joining process for soft materials such as aluminium alloys because it avoids many of the common problems of fusion welding. Commercial feasibility of the FSW process for harder alloys such as steels and titanium alloys awaits the development of cost effective and durable tools which lead to structurally sound welds consistently. Material selection and design profoundly affect the performance of tools, weld quality and cost. Here we review and critically examine several important aspects of FSW tools such as tool material selection, geometry and load bearing ability, mechanisms of tool degradation and process economics.