Showing 6 results for Interlayer
A.s. Razavi, H. Sabet,
Volume 4, Issue 1 (8-2018)
Abstract
In this research, the FSW Butt joint of commercial aluminum 1050 was investigated by using the 7075 aluminum alloy interlayer on the linear velocity of 30, 50 and 100 mm / min, and rotational speeds of 800 and 1200 rpm. A threaded cylindrical tool was used for joining of the 5 mm sheets. The OM, SEM, microhardness and tensile tests were done. The results shows that in sample with an interlayer at the condition of the 800 rpm and 30 mm/min the maximum tensile strength and hardness appeared and in the non-layered sample at the 800 rpm and 50 mm/min, the maximum tensile strength and hardness was obtained. The results shows that by using the interlayer the tensile strength and hardness were increase.
A. Abdollahzadeh, A. Shokuhfar,
Volume 5, Issue 1 (9-2019)
Abstract
In this study, friction stir butt welding of Mg and Al alloys with applying Zn interlayer was performed. To obtain optimum condition, a combination of two travel and three rotation speeds were selected. Mg-Zn and Mg-Al-Zn IMCs, Al solid solution and residual Zn, were the most common phases in the stirred zone, which eliminated the formation of Al-Mg intermetallics. The maximum mechanical properties were achieved for the joint fabricated at 35 mm/min and 600 rpm, caused to 24% improvement in tensile strength and around 3 times enhancement of elongation compared with Zn free sample FSWed at the same conditions. The fracture micrographs were consistent with corresponding ductility results. Fracture surfaces of Zn-added samples presented a fine texture with a mixture of brittle and ductile fracture feature, which was different from the coarse cleavage plane and fully brittle fracture of the joint without Zn interlayer.
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. Pourjafar, R. Dehmolaei, R. Alavi Zaree, Kh. Ranjbar, M.r. Tavakoli Shoushtari,
Volume 8, Issue 2 (1-2023)
Abstract
In this study, the effect of temperature on the microstructure and reactive layer at the interface between the Ti interlayer and the base metal related to the diffusion bonding of Zr702 to A516 low alloy steel was investigated. The joining was done using the spark plasma sintering technique at temperatures of 900, 950 and 1000°C for 30 minutes. Field Emission Scanning Electron Microscope (FESEM) equipped with EDS analysis was used to investigate the microstructure of the interfaces in various joints. Investigations showed that at all temperatures, with the diffusion of atoms and the formation of a reactive layer between the Ti interlayer and Zr702, no intermetallic phases, cracks, porosity and discontinuities were formed at their interfaces. . It was found that increasing the bonding temperature did not cause the formation of new phases and compounds in the interface and only increased the thickness of the reaction layer. The measurement of the thickness of the reactive layer showed that the maximum and minimum amounts of diffusion were 84 microns at 1000 °C and 64 microns at 900 °C respectively
A. Mahdavi Shaker, H. Momeni, A. Khorram, A. Yazdipour,
Volume 8, Issue 2 (1-2023)
Abstract
This study aimed to investigate the effect of electron beam welding parameters on the microstructural characteristics and mechanical properties of the dissimilar joint between 17-4PH precipitation hardening stainless steel and Ti6Al4V alloy. For this purpose, the welding of these two alloys was done without an interlayer and with an interlayer of copper with a thickness of 0.8 mm. Two different welding speeds of 0.7 and 0.9 m/min with four levels of beam offset (0, 0.2, 0.4 and 0.6 mm) from the center of the interlayer towards the steel were used to perform experiments. The results show that in the direct welding of titanium and steel, the joint structure consists of TiFe and TiFe2+TiCr2 intermetallic compounds with high hardness (about 900 Vickers). In the welding of titanium and steel by using the copper interlayer, the structure in the weld pool and the interface between the weld pool and steel includes a solid solution of copper and TiFe2 intermetallic compounds, and at the interface between the weld pool and titanium includes Ti+Ti2Cu and TiFe. The hardness of the welding zone in the samples welded with copper interlayer is about 400 Vickers. The highest value of hardness is observed at the interface between the weld pool and titanium alloy, as well as at the interface between the weld pool and steel, which is due to the presence of intermetallic compounds with high hardness. By increasing the welding speed and beam offset, the hardness decreases, which is due to the reduction of brittle intermetallic compounds in the joint structure. The welded sample with a welding speed of 0.9 m/min and beam offset of 0.6 mm has the highest shear strength equal to 160 MPa.
A. Mahdavi Shaker, H. Momeni, A. Khorram, A. Yazdipour,
Volume 9, Issue 1 (5-2023)
Abstract
This study aimed to investigate the effect of electron beam welding parameters on the microstructural characteristics and mechanical properties of the dissimilar joint between 17-4PH stainless steel and Ti6Al4V alloy. For this purpose, the welding of these two alloys was performed with an copper interlayer with a thickness of 1 mm. Two different welding speeds of 0.7 and 0.9 m/min with four levels of beam offset (0, 0.2, 0.4 and 0.6 mm) from the center of the interlayer towards the steel were used to accomplish the experiments. The results show that by using the copper interlayer with thickness of 1 mm, the cracks caused by the formation of intermetallic compounds are removed from the weld pool. At the interface between the titanium and the weld pool, at the beam offset of 0 and 0.2 mm, a solid solution of copper and TiCu2 intermetallic compounds is formed, while at the beam offset of 0.4 and 0.6 mm, a solid solution of copper and TiCu intermetallic compounds is formed. The weld pool, at the beam offset of 0 and 0.2 mm, consists of TiCr2+TiFe2 intermetallic compounds while at the beam offset of 0.4 and 0.6 mm, solid solution of iron (α-Fe), solid solution of copper and TiCu intermetallic compounds are formed. The highest value of hardness is observed at the interface between the weld pool and the titanium alloy, as well as at the interface between the weld pool and the steel, which is due to the presence of intermetallic compounds with high hardness in these regions. By increasing the welding speed and the beam offset, the hardness value decreases, which is due to the reduction of brittle intermetallic compounds in the joint structure. By increasing the beam offset from 0.4 mm to 0.6 mm at the speed of 0.7 m/min, the shear strength increases from 180 MPa to 210 MPa and at the speed of 0.9 m/min, the shear strength raises from 230 MPa to 250 MPa. The welded sample with the welding speed of 0.9 m/min and the beam offset of 0.6 mm has the highest shear strength equal to 250 MPa. The failure in all samples happened at the interface between the weld pool and the titanium alloy, which shows that the weakest region in the joint is this interface.
