A review on hot stamping

Large-Scale Fabrication of Boron Nitride Nanosheets and Their Utilization in Polymeric Composites with Improved Thermal and Mechanical Properties

Propulsion system development requires new, more affordable manufacturing techniques and technologies in a constrained budget environment, while future in-space applications will require in-space manufacturing and assembly of parts and systems. Marshall is advancing cuttingedge commercial capabilities in additive and digital manufacturing and applying them to aerospace challenges. The Center is developing the standards by which new manufacturing processes and parts will be tested and qualified. Rapidly evolving digital tools, such as additive manufacturing, are the leading edge of a revolution in the design and manufacture of space systems that enables rapid prototyping and reduces production times. Marshall has unique expertise in leveraging new digital tools, 3D printing, and other advanced manufacturing technologies and applying them to propulsion systems design and other aerospace materials to meet NASA mission and industry needs. Marshall is helping establish the standards and qualifications “from art to part” for the use of these advanced techniques and the parts produced using them in aerospace or elsewhere in the U.S. industrial base.

Additive manufacturing

Drug nanocrystals in the commercial pharmaceutical development process

Enhancing lubricant properties by nanoparticle additives

In this study, TiTaBN graded-composite coatings were deposited utilizing different process parameters on D2 steel and glass substrates using pulsed DC closed-field unbalanced magnetron sputtering (CFUBMS). The morphology and structure of the coatings were analyzed using scanning electron microscopy (SEM), energy-dispersive spectroscopy (EDS), X-ray photoelectron spectroscopy (XPS), and Raman spectroscopy. The hardness and critical load values of the coatings were determined using a microhardness tester and scratch tester, respectively. The tribological properties of the coatings were analyzed in different testing environments using a pin-on-disc tribometer. The properties of the coatings were found to be strongly affected by the coating parameters. The maximum thickness and hardness were obtained at the lowest nitrogen flow rate and highest frequency. Critical load values of coatings were increased with increased nitrogen flow rate. The low nitrogen flow rate and high frequency across the coatings...

Mechanical and Tribological Properties of TiTaBN Graded-Composite Coatings Deposited Using the CFUBMS Technique

Press hardening is employed in automotive industry to produce advanced high-strength steel components for safety and structural applications. In this hot forming process, the dimensional accuracy of produced components relies not only on an optimum friction level for the deformation of the workpiece, but it also gets affected by wear of the forming tools, which reduces the service life of the tool as well. It is desirable to enhance the durability of the tools by understanding the influence of contact conditions on tool wear. However, this is difficult to achieve in conventional tribological testing equipment. With this in view, the tribological behaviour of tool-workpiece material pairs at elevated temperatures has been studied in a newly developed experimental set-up simulating the conditions prevalent during interaction of the hot workpiece with the tool surface. The coefficients of friction of uncoated and Al-Si coated 22MnB5 steel decreased when the normal load increased. The influence of sliding velocity on the coefficient of friction was negligible for uncoated and Al-Si coated 22MnB5 steel. In the case of Al-Si coated 22MnB5 steel, adhesive material transfer of the Al-Si coating onto the tool steel surface was the main wear mechanism and this was also the reason for the higher and unstable friction coefficient when compared to uncoated 22MnB5 steel. In the case of uncoated 22MnB5 steel, adhesion was the main wear mechanism.

Simulative High Temperature Friction and Wear Studies for Press Hardening Applications

The friction and wear characteristics of several elastomers have been studied during reciprocating sliding conditions when lubricated with uncontaminated environmentally adapted lubricants and the ...

Friction and wear characteristics of elastomers in lubricated contact with EALs

Due to new environmental regulations, Pb-free engine bearing materials are becoming more common and there is a need for studying their tribological performance. Under severe and nonideal operating ...

Investigations into Seizure Behaviour of Pb-free Engine Bearing Materials Under Dry Condition

Lubricating grease is commonly used for lubricating ‘sealed and greased for life’ bearings. This grease lubricates the rolling contacts. It also provides an additional sealing function to protect the bearing against ingress of contamination. The sealing function of lubricating grease in the vicinity of the seal lip contact has been studied experimentally. The effects of the lubricant rheology on the migration of ingress particles has been examined. In grease, experimental results reveal that contaminant particles consistently migrate towards the sealing contact where the shear rate reaches its highest value. In contrast, for a Newtonian base oil and a non shear thinning elastic fluid, it has been observed that the migration effect takes place in the opposite direction, and brings particles away from the sealing contact. It is concluded that the sealing function of grease in the vicinity of the sealing contact is due to the fluid rheology and more specifically to the shear thinning behaviour of the lubricant.Copyright © 2010 by ASME

Braham Prakash

Papers

Mechanical and Tribological Properties of TiTaBN Graded-Composite Coatings Deposited Using the CFUBMS Technique

Simulative High Temperature Friction and Wear Studies for Press Hardening Applications

Friction and wear characteristics of elastomers in lubricated contact with EALs

Investigations into Seizure Behaviour of Pb-free Engine Bearing Materials Under Dry Condition

The Sealing Function of Grease: Contamination Migration in Grease Lubricated Radial Lip Seals