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Characterization of dynamic recrystallization parameters for a low carbon resulfurized free - cutting steel
, Article Materials and Design ; Vol. 53 , January , 2014 , pp. 910-914 ; ISSN: 02641275 ; Akbarzadeh, A ; Sharif University of Technology
2014
Abstract
The hot working behavior of a low carbon resulfurized free-cutting steel was studied by hot compression tests at temperature range of 1000-1200°C with strain rates of 0.001 to 1s-1. The conventional parameters such as activation energy of deformation and relationships between flow stress/strain and Zener-Hollomon parameter were determined. Both the critical stress and strain for initiation of dynamic recrystallization (DRX) were determined using: (1) strain hardening rate versus stress curve, (2) the natural logarithm of strain hardening rate versus strain curve, and (3) the constitutive equations. In summary, for low carbon resulfurized free - cutting steels, the activation energy of...
Hot Workability of a Free-cutting Steel with Severe Sulfur Segregation During Continuous Casting
, M.Sc. Thesis Sharif University of Technology ; Akbarzadeh, Abbas (Supervisor)
Abstract
Splitting in ingot cast structures and transverse cracks in continuous cast structures are the main problems of hot rolling of low carbon resulfurized free-cutting (LCRF) steels. Presence of high volume fraction of manganese sulfide inclusions in cast structure increases the risk of alligatoring in hot rolling. Because of high sulfur content of these steels and probability of formation of low melting point phases, minimum level of manganese and maximum level of copper and tin is necessary. Morphology of manganese sulfide is another important factor in hot forming of these steels, which can be controlled by level of deoxidation in steel making. In fact, MnS2 is present in fully killed...
Predicting crack initiation of solder joints with varying sizes under bending
, Article Journal of Electronic Materials ; 2019 ; 03615235 (ISSN) ; Farrahi, G. H ; Nourani, A ; Soroosh, F ; Sharif University of Technology
Springer New York LLC
2019
Abstract
The critical strain energy release rate for crack initiation, J ci , was measured under mode I loading for SAC305 solder joints between two copper substrates. Fracture tests were performed using double cantilever beam specimens at a strain rate of 0.03 s −1 . Different bond-line widths (i.e., joint size in the out-of-plane dimension) and thicknesses, were examined. The fracture force per unit width and J ci (the average value of four J-integral contours encircling the crack tip) were relatively insensitive to the width of the joint ranging from 8 mm to 21 mm. Variations in bond-line thickness (i.e., 150 μm, 250 μm and 450 μm) also had an insignificant influence on the fracture energy of...
Predicting crack initiation of solder joints with varying sizes under bending
, Article Journal of Electronic Materials ; 2019 ; 03615235 (ISSN) ; Farrahi, G. H ; Nourani, A ; Soroosh, F ; Sharif University of Technology
Springer New York LLC
2019
Abstract
The critical strain energy release rate for crack initiation, J ci , was measured under mode I loading for SAC305 solder joints between two copper substrates. Fracture tests were performed using double cantilever beam specimens at a strain rate of 0.03 s −1 . Different bond-line widths (i.e., joint size in the out-of-plane dimension) and thicknesses, were examined. The fracture force per unit width and J ci (the average value of four J-integral contours encircling the crack tip) were relatively insensitive to the width of the joint ranging from 8 mm to 21 mm. Variations in bond-line thickness (i.e., 150 μm, 250 μm and 450 μm) also had an insignificant influence on the fracture energy of...