Showing 4 results for Titanium
M. Sadeghi Gogheri, M. Shabani, E. Mirzapour, M. Kasiri, K. Amini,
Volume 2, Issue 1 (8-2016)
Abstract
In this study, commercially pure titanium and aluminum alloy 5083 in connection rotational speed of 1120 rpm and a feed rate of 50 mm per minute for butt welding by friction stir welding has been successfully completed. Micro-structure, hardness and tensile test was conducted on the connection. Welding area is a composite of aluminum and titanium particles that the particles plays an important role in increasing hardness and tensile strength. Welding area is also has three areas. Vickers hardness is 480 times the area of welding means that the hardness in the area of the base metal of titanium and aluminum increased by 16% and 60% for titanium aluminum intermetallic compounds is created in the area is weld.
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Volume 6, Issue 1 (8-2020)
Abstract
In this research, effect of time and temperature of TLP process on the microstructure, mechanical properties and corrosion resistance of CP-Ti to 316L stainless steel joint evaluated. For this purpose pure copper foil with 100 µm thickness was used as interlayer and joining process carried out at 950˚C, 1000˚C and 1050˚C and for 90, 120 and 150 minutes. After the joining process, shear and micro-hardness test and corrosion resistance were applied in the samples. The test results revealed that the shear strength of the sample 1000˚C is better than two other soaking temperatures. The main reason was the formation of less intermetallic compounds at the interface, as well as the presence of less athermally solidification zone area. Microstructural examinations for the sample after TLP at 950˚C revealed no iron and titanium bearing intermetallic compounds in the interface while for two other samples, there exist considerable amount of intermetallics in the microstructure. Corrosion test results showed that the resistance against corrosion depends on the intermetallic compounds formed in the interface. Intermetallic phases includes FeTi, TiCu, Ti2Cu, and TiCu2. The sample prepared at 1000˚C for 120 minutes had less intermetallic compounds and as a result, had the best corrosion resistance. Fe and Ti containing intermetallics had good corrosion resistance in simulated body fluid, as comparison with Ti and Cu containing compounds.
S. Z. Anvari, S. Daneshpour , S. Oshaghi,
Volume 6, Issue 2 (12-2020)
Abstract
In this study, diffusion bonding between titanium and AISI 304 austenitic stainless steel by Ag interlayer was investigated. In order to carry out this research, samples prepared after surface preparation were placed inside the fixture and placed at the temperatures of 750,800 and 850 °C in the 30,60 and 90 min in the furnace under argon protective gas. The phase transformation and microstructure of diffusion bonding interfaces of the joints were studied using optical microscopy, scanning electron microscopy and x-ray diffraction. Then, the hardness of the samples was measured using a hardness test apparatus. Finally, the samples were tested after being placed in the shear strength test holder using a pressure test device and the shear strength of the samples was measured. Examination of optical microscopic images shows the diffusion of silver in titanium and the partial diffusion of silver in stainless steel. On the other hand, increasing the temperature increases the diffusion region as well as increasing the grain size in the specimens. SEM images from the samples also confirmed the diffusion of silver in titanium and partially diffusion into stainless steel. The results of the XRD test on the samples showed that the temperature rise to 800 °C leads to the formation of TiAg and Ag3Fe2 intermetallic compounds, which the existence of TiAg intermetallic compound increases the hardness of the sample. For this reason, the sample at 800 °C showed the highest hardness. The shear strength of the samples showed that the increase in temperature increased the shear strength of the samples and decreased the shear strength by increasing the temperature above 850 ° C due to the formation of brittle intermetallic compounds.
A. Etemadi, M. Kasiri-Asgarani, H. R. Bakhsheshi-Rad, M. Sadeghi Gogheri,
Volume 9, Issue 2 (1-2024)
Abstract
In this research, dissimilar joining of biodegradable AZ31 alloy to Ti-6Al-4V titanium alloy by rotary friction welding method was investigated with aim of preparation of pin or screw for orthopedic applications. optical and scanning electron microscope (sem) were used to investigate the microstructure, x-ray diffraction was conducted for phase analysis, torsion and micro-hardness tests were carried out to investigate mechanical properties, and polarization and electrochemical impedance spectroscopy were employed to evaluate corrosion resistance. in the welding procedure, rotational speed of 1100, 1200 and 1300 rpm and friction time of 2 and 4 seconds were considered as variable parameters, and two parameters of friction pressure and forge pressure were considered as constant parameters at 50 and 40 MPa, respectively. The microstructure of the joint zone showed that there is no deformation in the titanium alloy side. However, in the magnesium side, the greatest amount of deformation occurred with the distance from the joint line, where weld center zone (CZ), dynamic recrystallization zone (DRX), thermomechanical affected zone (TMAZ) and partial deformation zone (PDZ) are detected. The formation of intermetallic phases such as Mg2AlZn, Ti3Al and also the refining the grains size is the main reason for increasing the hardness of the magnesium side near the joint line up to 150 HV. The results of the torsion test showed that the welded sample has the highest shear strength of 81.51 MPa and also the highest corrosion resistance among other samples at a rotation speed of 1200 rpm and a friction time of 4 seconds.
