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.
Breakthrough in nanoresearch - Quantum chains in graphene nanoribbons
09.08.2018 | Empa - Eidgenössische Materialprüfungs- und Forschungsanstalt
UNH Researchers find seed coats could lead to strong, tough, yet flexible materials
08.08.2018 | University of New Hampshire
Researchers from TU Graz and their industry partners have unveiled a world first: the prototype of a robot-controlled, high-speed combined charging system (CCS) for electric vehicles that enables series charging of cars in various parking positions.
Global demand for electric vehicles is forecast to rise sharply: by 2025, the number of new vehicle registrations is expected to reach 25 million per year....
Proteins must be folded correctly to fulfill their molecular functions in cells. Molecular assistants called chaperones help proteins exploit their inbuilt folding potential and reach the correct three-dimensional structure. Researchers at the Max Planck Institute of Biochemistry (MPIB) have demonstrated that actin, the most abundant protein in higher developed cells, does not have the inbuilt potential to fold and instead requires special assistance to fold into its active state. The chaperone TRiC uses a previously undescribed mechanism to perform actin folding. The study was recently published in the journal Cell.
Actin is the most abundant protein in highly developed cells and has diverse functions in processes like cell stabilization, cell division and muscle...
Scientists have discovered that the electrical resistance of a copper-oxide compound depends on the magnetic field in a very unusual way -- a finding that could help direct the search for materials that can perfectly conduct electricity at room temperatur
What happens when really powerful magnets--capable of producing magnetic fields nearly two million times stronger than Earth's--are applied to materials that...
The quality of materials often depends on the manufacturing process. In casting and welding, for example, the rate at which melts solidify and the resulting microstructure of the alloy is important. With metallic foams as well, it depends on exactly how the foaming process takes place. To understand these processes fully requires fast sensing capability. The fastest 3D tomographic images to date have now been achieved at the BESSY II X-ray source operated by the Helmholtz-Zentrum Berlin.
Dr. Francisco Garcia-Moreno and his team have designed a turntable that rotates ultra-stably about its axis at a constant rotational speed. This really depends...
If certain signaling cascades are misregulated, diseases like cancer, obesity and diabetes may occur. A mechanism recently discovered by scientists at the Leibniz- Forschungsinstitut für Molekulare Pharmakologie (FMP) in Berlin and at the University of Geneva has a crucial influence on such signaling cascades and may be an important key for the future development of therapies against these diseases. The results of the study have just been published in the prestigious scientific journal 'Molecular Cell'.
Cell growth and cell differentiation as well as the release and efficacy of hormones such as insulin depend on the presence of lipids. Lipids are small...
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14.08.2018 | Life Sciences
14.08.2018 | Life Sciences