Computational modelling of dynamic recrystallisation of Ni-based superalloy during linear friction welding

Linear friction welding (LFW) is an advanced joining technology used for manufacturing and repairing complex assemblies like blade integrated disks (blisks) of aeroengines. This paper presents an integrated multiphysics computational modelling for predicting the thermomechanical-microstructural processes of IN718 alloy (at the component-scale) during LFW. Johnson–Mehl–Avrami-Kolmogorov (JMAK) model was implemented for predicting the dynamic recrystallisation of γ grain, which was coupled with thermomechanical modelling of the LFW process. The computational modelling results of this paper agree well with experimental results from the literature in terms of γ grain size and weld temperature. Twenty different LFW process parameter configurations were systematically analysed in the computations by using the integrated model. It was found that friction pressure was the most influential process parameter, which significantly affected the dynamic recrystallisation of γ grains and weld temperature during LFW. The integrated multiphysics computational modelling was employed to find the appropriate process window of IN718 LFW.

Microstructure and Mechanical Properties of Aluminum Alloy/Stainless Steel Dissimilar Ring Joint Welded by Inertia Friction Welding

In recent years, studying the weldability of a dissimilar metal hybrid structure, with the potential to make full use of their unique benefits, has been a research hotspot. In this article, inertia friction welding was utilized to join Φ130 forged ring of 2219 aluminum alloy with 304 stainless steel. Optical observation (OM), electron back scattering diffraction (EBSD), and scanning electron microscopy (SEM) were utilized to examine the joint microstructure in depth. Depending on the research, a significant thermal–mechanical coupling effect occurs during welding, resulting in inadequate recrystallization on aluminum-side thermo-mechanically affected zone (TMAZ) and forming zonal features. The crystal orientation and grain size of each TMAZ region reflect distinct differences. On the joint faying surface, the growth of intermetallic compounds (IMCs) is inhibited by a fast cooling rate and metallurgical bonding characteristics were found depending on the discontinuous distribution of IMCs. The average joint tensile strength can reach 161.3 MPa achieving 92.2% of 2219-O; fracture occurs on aluminum-side base metal presenting ductile fracture characteristics.

Studying phase formation of 12Х18Н10Т alloy and copper after friction welding

The technology of joining alloy 12X18H10T and copper has been studied. The use of friction welding is proposed. Modern development of technology requires the use of new technologies and materials. Despite the increase in the use of composite materials, and especially on the basis of the polymer matrix, metal alloys remain indispensable. Due to their physical and mechanical properties, metal-based alloys are used in rocket and space technology, mechanical engineering, and other industries. Goal. The aim of this work is the reason for the decrease in the mechanical properties of the connection 12Х18Н10Т – М1, which were obtained under suboptimal conditions. Friction welding was developed in early 1956 in the USSR. Since the 1960s, other countries have also begun to develop friction welding. This tool is a type of pressure welding, during which the metal is heated by friction of one of the parts of the product. At the end of the process, the final connection takes place. This type of welding is used in aircraft construction, rocketry, machine building, etc. In Ukraine, research in this direction is conducted at the Eugene Paton Institute of Electric Welding. The parameters of the friction welding technological process are considered. Results. The samples of welded joints 12Kh18N10T + M1 were studied. The following methods were used: mechanical tests; metallographic and electro-microscopic studies; hardness measurements; micro-X-ray spectral study. Originality. Welding joints with low strength were investigated; they were obtained for the following parameters: relative rotation speed 0.4 m/s, pressure during heating 80 MPa, pressure during forging 80 MPa, upset value 9 * 10-3 m samples with low strength varied in the deformed layer of steel from the joint surface to the base metal from 3240 MPa to 2450 MPa; in a deformed copper layer from 1020 MPa to 690 MPa. On samples that had high strength, the microhardness varied on the steel side from 2260 MPa in the contact surface to 2160 MPa, and in copper from 590 MPa to 460 MPa. Fig. 1 shows the microstructure of the deformed zones of the welded joint 12X18H10T, obtained according to the optimal parameters. Practical value. The reason for the decrease in the mechanical properties of the 12Х18Н10Т – М1 joint was established.