Search published articles


Showing 3 results for Tamizi
Optimization of FSW parameters for mechanical properties of Nano/UFG Aluminum- scandium alloys by using design of experiment method
M. Yousefieh, M. Tamizifar, S.m.a. Boutorabi, E. Borhani,
Volume 3, Issue 2 (Journal OF Welding Science and Technology of Iran 2018)
Abstract
In the present research, the parameters of FSW process were optimized for the mechanical properties of thin aluminum- scandium alloys by a design of experiment (DOE) technique. The optimum conditions providing the highest mechanical properties were found by this method. Among the three factors and three levels tested, it was concluded that the tool rotational speed had the most significant effect on the mechanical properties and the travel speed had the next most significant effect. The effect of tool tilt angle was less important when compared to the other factors. The EBSD results demonstrated a recrystallized equi axial structure and the existence of a mixture of B and Ccomponents in the weld nugget.
Investigation of microstructure and physical properties in nanocomposite solder reinforced with various percent of graphene nanosheets (SAC0307+GNSs)
S. Azghandirad, M. Movahedi, A. Kokabi, M. Tamizi,
Volume 8, Issue 1 (Journal OF Welding Science and Technology 2022)
Abstract
Development of electronic industries, compression of electronic equipment, and removing lead from electronic circuits for environmental issues, resulted in a significant challenge in design and development of tin-based lead-free solders with physical and mechanical properties similar to old tin-lead alloys. In this regard, the set of Sn-Ag-Cu alloys with eutectic and near eutectic compositions have been proposed to replace Sn-Pb solders. As a lead-free solder alloy, low melting point, high reliability, and compatibility with various fluxes are among the properties of this category of alloys. In order to improve the properties of the joint, these solders are sometimes reinforced with different nanoparticles. In this study, Sn0.3Ag0.7Cu compound reinforced with graphene nanosheets with different weight percentages (0, 0.05, 0.1, and 0.2) was studied. Microstructure of the alloys was investigated by scanning electron microscopy(SEM) and optical microscopy. Melting temperature, wetting behavior and electrical resistivity of the solders were evaluated. According to the results, by adding graphene nanosheets, the wetting angle of the solder first decreased and then increased. This parameter showed the optimal amount for sample containing %0.1 graphene nanosheets with a %10 reduction. The melting point and electrical resistance of the solder alloy did not change significantly with compositing. With the addition of graphene nanosheets, the thickness of the intermetallic compounds Cu6Sn5 present at the interface between copper and solder was reduced up to %30.
 

Investigation of microstructure and mechanical properties of lead free composite solder containing cobalt microparticles produced by accumulative roll bonding
M.h. Nourmohammadi, M. Movahedi, A.h. Kokabi, M. Tamizi,
Volume 9, Issue 1 (Journal OF Welding Science and Technology 2023)
Abstract
The miniaturization and compaction trends in electronic equipment and the removal of lead (Pb) element from solder alloys due to environmental considerations have created a great challenge in the field of designing and developing of new solder alloys. Therefore, researchers have recently focused on composite solder alloys using reinforcing particles to improve the reliability of lead-free solders. In this research, SAC0307 solder alloys (99 wt.% Sn, 0.3 wt.% Ag, and 0.7 wt.% Cu) with different percentages of cobalt microparticles were made by the Accumulative Roll Bonding (ARB) method. Then, the effect of the particles on wettability, microstructures and mechanical characteristics of solder alloys was investigated. The lowest contact angle was 23◦in 0.2 wt.% cobalt sample. By adding cobalt to the solder matrix, the size of intermetallic compounds (IMCs), Cu6Sn5 and Ag3Sn, decreased and the percentage of eutectic phases increased. The shape of the interfacial intermetallic compounds changed from scallop to layer shape by adding cobalt, and their average thickness increased about 13-71% in composite samples. The shear strength of solders increased up to 38% by enhancement of cobalt microparticles in the solder alloy containing 0.4 wt.% cobalt; however, shear strength was decreased in the composite solder containing 1 wt.% cobalt due to the agglomeration of microparticles. The shear fracture surfaces showed that the nature of the fracture changed from ductile fracture in the form of elongated dimples to brittle fracture in the form of cleavage with the increase in the percentage of cobalt microparticles. The composite solder alloys containing 0.2-0.4 wt.% Co have the best wettability behavior and tensile shear strength.

Page 1 from 1     

© 2024 CC BY-NC 4.0 | Journal of Welding Science and Technology of Iran

Designed & Developed by : Yektaweb