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.
One in 5 materials chemistry papers may be wrong, study suggests
15.12.2017 | Georgia Institute of Technology
Scientists channel graphene to understand filtration and ion transport into cells
11.12.2017 | National Institute of Standards and Technology (NIST)
DNA molecules that follow specific instructions could offer more precise molecular control of synthetic chemical systems, a discovery that opens the door for engineers to create molecular machines with new and complex behaviors.
Researchers have created chemical amplifiers and a chemical oscillator using a systematic method that has the potential to embed sophisticated circuit...
MPQ scientists achieve long storage times for photonic quantum bits which break the lower bound for direct teleportation in a global quantum network.
Concerning the development of quantum memories for the realization of global quantum networks, scientists of the Quantum Dynamics Division led by Professor...
Researchers have developed a water cloaking concept based on electromagnetic forces that could eliminate an object's wake, greatly reducing its drag while...
Tiny pores at a cell's entryway act as miniature bouncers, letting in some electrically charged atoms--ions--but blocking others. Operating as exquisitely sensitive filters, these "ion channels" play a critical role in biological functions such as muscle contraction and the firing of brain cells.
To rapidly transport the right ions through the cell membrane, the tiny channels rely on a complex interplay between the ions and surrounding molecules,...
The miniaturization of the current technology of storage media is hindered by fundamental limits of quantum mechanics. A new approach consists in using so-called spin-crossover molecules as the smallest possible storage unit. Similar to normal hard drives, these special molecules can save information via their magnetic state. A research team from Kiel University has now managed to successfully place a new class of spin-crossover molecules onto a surface and to improve the molecule’s storage capacity. The storage density of conventional hard drives could therefore theoretically be increased by more than one hundred fold. The study has been published in the scientific journal Nano Letters.
Over the past few years, the building blocks of storage media have gotten ever smaller. But further miniaturization of the current technology is hindered by...
11.12.2017 | Event News
08.12.2017 | Event News
07.12.2017 | Event News
15.12.2017 | Power and Electrical Engineering
15.12.2017 | Materials Sciences
15.12.2017 | Life Sciences