Effects Of Process Parameters On The Transient Liquid Phase Bonding Of Dissimilar Materials

Transient liquid phase (TLP) bonding has become a very attractive method of joining similar and dissimilar difficult-to-weld advanced materials. The effects of process parameters on the joint microstructure of TLP bonded nickel-based superalloy IN738 and cobalt metal using Nicrobraz 150 interlayer are investigated in this research. It is discovered that adequate processing time (tf) is required to prevent formation of deleterious eutectic that is known to degrade the mechanical properties of the joint. Increase in temperature to a certain point reduces the size of the eutectic in the joint due to increase in diffusivity with increase in temperature. However, a further increase in temperature above this temperature produced a larger width of the eutectic at the joint because of the overriding effect of solubility on diffusivity at higher temperatures. The eutectic in dissimilar IN 738/Co is asymmetrically distributed within the joint and this is caused by liquid-state diffusion, which has been generally ignored in the discussion of TLP bonding of dissimilar materials in the literature. In contrast to the expectation that rapid atomic diffusion in the liquid would reduce the processing time (tf) required to completely eliminate the eutectic from the joint region through diffusional solidification, the occurrence of liquid-state diffusion significantly prolonged the processing time. This requires adequate consideration in the use of TLP bonding for joining dissimilar materials.

The book presents a complete overview on the topic of Transient Liquid Phase Bonding (TLPB) which has many high-tech applications, ranging from the production and repair of turbine engines in the aerospace industry, to nuclear power plants and the connection of circuit lines in the microelectronics industry. The TLPB process and its specific applications are presented in great detail: Self-Bonding of Pure Materials; Bonding Different Pure Materials; Self-Bonding of Composites; Self-Bonding of Simple Alloys; Self-Bonding of Complex Alloys; Bonding Same-Base Alloys; Bonding Different-Base Alloys; Bonding Ceramics to Ceramics; Bonding Ceramics to Metals. The book references 483 original resources and includes their direct web link for in-depth reading.

Transient liquid phase (TLP) bonding has proven to be the preferred method for joining extremely difficult-to-weld advanced materials, including similar and dissimilar superalloys. In this work, an approach that combines experiments and theoretical simulations are used to investigate the effect of temperature gradient (TG) in a vacuum furnace on the temperature distribution in TLP bonded samples. When joining similar materials by this technique, the simulated results with experimental verifications show that, irrespective of where the samples are placed inside the vacuum furnace, a TG in the furnace can translate into a symmetric temperature distribution in bonded samples provided the diffusion direction is parallel to the source of heat emission. In addition, the effects of TLP bonding parameters on the joint microstructure were investigated during the joining of nickel-based IN738 and CMSX-4 single crystal (SX) superalloys. An increase in holding time and reduction in gap size reduces the width of eutectic product that forms within the joint region. It was also found that Liquid-state diffusion (LSD) can occur and have significant effects on the microstructure of dissimilar TLP bonded joints even though its influence is often ignored during TLP bonding. The occurrence of LSD produced single crystal joint when a SX and polycrystal substrate were bonded. This formation of a SX joint which cannot be exclusively produced by solid-state diffusion has not been previously reported in the literature.

The book presents a complete overview on the topic of Transient Liquid Phase Bonding (TLPB) which has many high-tech applications, ranging from the production and repair of turbine engines in the aerospace industry, to nuclear power plants and the connection of circuit lines in the microelectronics industry. The TLPB process and its specific applications are presented in great detail: Self-Bonding of Pure Materials; Bonding Different Pure Materials; Self-Bonding of Composites; Self-Bonding of Simple Alloys; Self-Bonding of Complex Alloys; Bonding Same-Base Alloys; Bonding Different-Base Alloys; Bonding Ceramics to Ceramics; Bonding Ceramics to Metals. The book references 483 original resources and includes their direct web link for in-depth reading.

This report supplies information on joining processes applicable to titanium and its alloys in sheet metal applications, primarily related directly to airframe construction. Although the material presented here does not cover all titanium joining processes, and omits such processes as plasma-arc, submerged-arc, electroslag, flash, and high-frequency resistance welding, the data presented cover materials up to 2-inches thick in some cases and the report should be useful to anyone seeking titanium joining information. The joining processes covered fall into five categories: welding, brazing, metallurgical bonding (diffusion and deformation bonding), adhesive bonding, and mechanical fastening. The fusion welding processes that are discussed in detail include gas tungsten arc, gas metal arc, arc spot, and electron beam. The resistance processes give extended coverage are spot, roll spot, and seam welding. (Author).

Magnesium-based materials are rapidly emerging in recent years to primarily assist in mitigating global warming and for health benefits. They are seen as materials of the future due to their lightweight, nutritional characteristics and abundance on Earth. Their applications are in a wide array of engineering and biomedical sectors, promising a multi-billion-dollar market in the very near future. The applicability of magnesium-based materials also suits the current emphasis on sustainability and a greener earth. This book was thus conceptualized and highlights important areas of current research and future directions including fundamental and applied principles related to primary and secondary processing types, microstructural evolution, machining, joining, and the past and current application scenario of magnesium-based materials.

Joining Processes is aimed at scientists and engineers who need to specify effective means of joining metals and ceramics, and also for undergraduates whose studies encompass joining processes. Joining Processes provides a brief review of the spectrum of joining processes ranging from fusion welding to adhesive bonding, followed by a detailed introduction to brazing, diffusion bonding and their hybrid processes. This book also describes the scientific principles of the joining processes and provides practical information about the optimum selection of joining materials, joint designs and processing parameters. The effects of both similarities and significant differences of the processes on joint properties are emphasised and illustrated by descriptions of case histories of successful applications.

This book brings together the latest advances in, and applications of, manufacturing science and engineering. It comprises 976 papers, selected from among 3062 papers which were submitted by universities and industrial laboratories all over the world. All of chosen papers were subjected to strict peer-review.

Joining Processes for Dissimilar and Advanced Materials describes how to overcome the many challenges involved in the joining of similar and dissimilar materials resulting from factors including different thermal coefficients and melting points. Traditional joining processes are ineffective with many newly developed materials. The ever-increasing industrial demands for production efficiency and high-performance materials are also pushing this technology forward. The resulting emergence of advanced micro- and nanoscale material joining technologies, have provided many solutions to these challenges. Drawing on the latest research, this book describes primary and secondary processes for the joining of advanced materials such as metals and alloys, intermetallics, ceramics, glasses, polymers, superalloys, electronic materials and composites in similar and dissimilar combinations. It also covers details of joint design, quality assurance, economics and service life of the product. Provides valuable information on innovative joining technologies including induction heating of metals, ultrasonic heating, and laser heating at micro- and nanoscale levels Describes the newly developed modelling, simulation and digitalization of the joining process Includes a methodology for characterization of joints