Showing 5 results for Interface
Razaghian A., Yu D., Chandra T.,
Volume 2, Issue 3 (9-2005)
Abstract
Fracture behavior of a 7075 aluminium alloy reinforced with 15 Vol%. SiC particles was studied after T6 and annealing heat treatments under uniaxial tensile loading at room temperature. The scanning electron microscopy of fractured surfaces and EDS analysis showed:, that fracture mechanism changed from due mainly to fractured particle in T6 condition to interface decohesion in samples in annealed state. Different fracture mechanisms in annealed and T6 conditions can be ascribed mainly to the significant difference in the stress concentration levels around the particles. In T6 condition, very high local stress sufficient to cause fracture of particle can be generated during loading, while the presence of large precipitates at the particle/matrix interface produced interface decohesion leading to final fracture in the annealed state.
E. Maleki, K. Reza Kashyzadeh,
Volume 14, Issue 4 (12-2017)
Abstract
Hardened nickel coating is widely used in many industrial applications and manufacturing processes because of its benefits in improving the corrosion fatigue life. It is clear that increasing the coating thickness provides good protection against corrosion. However, it reduces the fatigue life. Thus, applying a thin layer of coated nickel might give an acceptable corrosion protection with minimum loss of the fatigue life. In the present study, the effects of hardened nickel coating with different thicknesses on the fatigue behavior of CK45 mild steel were experimentally investigated. After conducting the experimental tests, we carried out two different modeling approaches of finite element method (FEM) and artificial neural network (ANN). In the FEM modeling, an attempt was made to analyze the fatigue of the components by modeling the interface phase between the base metal and coating more accurately and using the spring elements; ANNs were developed based on the back propagation (BP) error algorithm. The comparison of the obtained results from FEM and ANN modeling with the experimental values indicates that both of the modeling approaches were tuned finely.
H. Mirzakouchakshirazi, A. Eivani, Sh. Kheirandish,
Volume 14, Issue 4 (12-2017)
Abstract
Effects of annealing treatment after equal channel angular pressing (ECAP) on the interface properties and shear bond strength of Al/Cu bimetallic rods were investigated. For the as-deformed samples, the one with two passes of ECAP indicated higher shear bond strength. Formation of a layer of intermetallic compounds after annealing treatment is confirmed. In general, by increasing annealing temperature, thickness of intermetallic compounds at the interface increases. Shear bond strength was initially reduced by annealing at 200, 250 and 300 ͦ C and increased at 350 ͦ C. With further increase in annealing temperature to 400 ͦ C, shear bond strength slightly decreased which is correlated to the increased thickness of the intermetallic compounds.
M. Gholami, M. Divandari,
Volume 15, Issue 4 (12-2018)
Abstract
Centrifugal casting process, in both horizontal and vertical mode, is considered as an efficient method to produce bimetallic components. Al/Cu65Zn35 couples were prepared by the vertical centrifugal casting process. In this study, different volume of molten aluminum having melt-to-solid (m/s) volume ratios (VR) of 1.5 and 2.5, were cast into preheated brass bush rotating at 800, 1600, and 2000 (rpm), respectively. The thickness of the interface, which is composed of three different zones, is depended on the rotational speed and the (VR) and was at least 490µm (at VR=1.5 and 2000 rpm) and at most 1480 µm (at VR=2.5 and 800 rpm). The results of optical microscopy, energy dispersive X-ray spectroscopy (EDS), and X-ray diffraction analysis showed that the interface layers are composed of Al2Cu5Zn4, Al3Cu3Zn, Al2Cu precipitates dispersed in the matrix and finally α-Al/Al2Cu anomalous eutectic structure near the aluminum side. Gas pore entrapment and oxide film entrainment defect was detected within the interface next to the aluminum base metal.
E. Shahmohamadi, A. Mirhabibi, F. Golestanifard,
Volume 16, Issue 3 (9-2019)
Abstract
An accurate prediction of reaction kinetics of silicon nitridation is of great importance in designing procedure of material production and controlling of reaction. The main purpose of the present study is to investigate the effect of temperature on the kinetics of reaction bonded silicon nitride (RBSN) formation. To achieve this, nitrogen diffusion in the silicon nitride layer is considered as a reaction controlling factor and sharp interface method based on this theory is used to develop the analytical model. In the developed model, the variations in the size of silicon particles are calculated for the whole reaction. In the experimental phase, the extent of nitridation is measured for different reaction temperatures and 4 different reaction times and then, the occurrence of full nitridation is shown by EDS analysis. Furthermore, an analytical approach was established for describing the kinetics of compound formation and the performance of the developed model is evaluated through statistical analysis. There was good agreement between experimental data and predictions of the developed model which demonstrates the accuracy of considered presumptions and reaction mechanisms. An accurate prediction of reaction kinetics of silicon nitridation is of great importance in designing procedure of material production and controlling of reaction. The main purpose of the present study is to investigate the effect of temperature on the kinetics of reaction bonded silicon nitride (RBSN) formation. To achieve this, nitrogen diffusion in the silicon nitride layer is considered as a reaction controlling factor and sharp interface method based on this theory is used to develop the analytical model. In the developed model, the variations in the size of silicon particles are calculated for the whole reaction. In the experimental phase, the extent of nitridation is measured for different reaction temperatures and 4 different reaction times and then, the occurrence of full nitridation is shown by EDS analysis. Furthermore, an analytical approach was established for describing the kinetics of compound formation and the performance of the developed model is evaluated through statistical analysis. There was good agreement between experimental data and predictions of the developed model which demonstrates the accuracy of considered presumptions and reaction mechanisms.
