The high mechanical strength and corrosion resistant nature of oxide dispersion strengthened (ODS) superalloys puts them in demand for use in extreme applications such as turbine engines and heat exchangers. Much of their suitability for these applications is derived from their carefully tailored microstructures. Unfortunately some joining methods, like welding, can alter the desirable microstructures and therefore the properties of the superalloy.
Transient Liquid Phase (TLP) diffusion bonding has emerged as a potential joining technique for advanced alloys when fusion welding and other solid state processes are not suitable. The process involves using an interlayer between the surfaces to be bonded. The interlayer contains materials that lower the melting point. At the bonding temperature, which is below the melting temperature of the parent alloy, the interlayer melts and a joint forms by isothermal solidification.
In the present work, R.K. Saka and T.I. Khan of the University of Calgary, used Transient Liquid Phase diffusion bonding to join Inconel MA 758 using nickel based interlayers.
The researchers investigated the effect of interlayer composition, bonding time and the use of post-bond heat treatment on microstructural developments at the joint region. They found that the hold time at the bonding temperature affected the rate of isothermal solidification during the TLP bonding process. They also found that altering the hold time could produce a joint free from deleterious centerline eutectic structures. The formation of intermetallic precipitates adjacent to the joint interface were observed for bonds made using all four interlayers and a proper selection of interlayer composition was shown to reduce precipitation. The use of post-bond heat treatment was also found to help homogenization of the joint microstructure.
Melting solid below the freezing point
23.01.2017 | Carnegie Institution for Science
An innovative high-performance material: biofibers made from green lacewing silk
20.01.2017 | Fraunhofer-Institut für Angewandte Polymerforschung IAP
For the first time ever, a cloud of ultra-cold atoms has been successfully created in space on board of a sounding rocket. The MAIUS mission demonstrates that quantum optical sensors can be operated even in harsh environments like space – a prerequi-site for finding answers to the most challenging questions of fundamental physics and an important innovation driver for everyday applications.
According to Albert Einstein's Equivalence Principle, all bodies are accelerated at the same rate by the Earth's gravity, regardless of their properties. This...
An important step towards a completely new experimental access to quantum physics has been made at University of Konstanz. The team of scientists headed by...
Yersiniae cause severe intestinal infections. Studies using Yersinia pseudotuberculosis as a model organism aim to elucidate the infection mechanisms of these...
Researchers from the University of Hamburg in Germany, in collaboration with colleagues from the University of Aarhus in Denmark, have synthesized a new superconducting material by growing a few layers of an antiferromagnetic transition-metal chalcogenide on a bismuth-based topological insulator, both being non-superconducting materials.
While superconductivity and magnetism are generally believed to be mutually exclusive, surprisingly, in this new material, superconducting correlations...
Laser-driving of semimetals allows creating novel quasiparticle states within condensed matter systems and switching between different states on ultrafast time scales
Studying properties of fundamental particles in condensed matter systems is a promising approach to quantum field theory. Quasiparticles offer the opportunity...
19.01.2017 | Event News
10.01.2017 | Event News
09.01.2017 | Event News
23.01.2017 | Process Engineering
23.01.2017 | Physics and Astronomy
23.01.2017 | Life Sciences