In alignment with the Materials Genome Initiative and as the product of a workshop sponsored by the US National Science Foundation, we define a vision for materials laboratories of the future in alloys, amorphous materials, and composite materials; chart a roadmap for realizing this vision; identify technical bottlenecks and barriers to access; and propose pathways to equitable and democratic access to integrated toolsets in a manner that addresses urgent societal needs, accelerates technological innovation, and enhances manufacturing competitiveness. Spanning three important materials classes, this article summarizes the areas of alignment and unifying themes, distinctive needs of different materials research communities, key science drivers that cannot be accomplished within the capabilities of current materials laboratories, and open questions that need further community input. Here, we provide a broader context for the workshop, synopsize the salient findings, outline a shared vision for democratizing access and accelerating materials discovery, highlight some case studies across the three different materials classes, and identify significant issues that need further discussion.
Note: When clicking on a Digital Object Identifier (DOI) number, you will be taken to an external site maintained by the publisher.
Some full text articles may not yet be available without a charge during the embargo (administrative interval).
What is a DOI Number?
Some links on this page may take you to non-federal websites. Their policies may differ from this site.
-
Abstract Graphical abstract -
A film adhesive is commonly used to form the bond line between composite or metal parts. The bond line's quality and performance can be affected by defects such as voids, impurities, agglomerations, and other structural issues found within it; in addition, defects can form due to damage or delamination. Identifying these defects is possible with non-destructive evaluation (NDE). In this paper, the joule-heating effect through carbon nanofibers (CNF) and carbon nanotubes (CNT) modified film adhesive will be used along with infrared thermography for bond line defect inspection. Due to the difference in the electrical conductivity between the modified epoxy and the defect, joule heating can cause a different temperature at the defect; thus, in theory, the defect can be viewed by infrared thermography. The percentage of carbon nanofiller in a film adhesive changes the measurement quality due to its relationship to electrical conductivity. An Acrylonitrile Butadiene Styrene (ABS) equilateral triangle defect with 30 mm sides was used inside bond line samples. These bond lines were composed of epoxy and nanofillers of CNF and CNT at various concentrations. Each concentration was evaluated individually and bonded onto two single-ply CFRP coupons. In this study, the feasibility of using carbon nanofillers of different concentrations as a medium for identifying and characterizing defects through NDE infrared thermography was investigated and validated the effectiveness of this new NDE approach. In the future, aligning nanofiller for bond lines could be a potential research direction to improve upon what this study strives to achieve.more » « less
-
Well-dispersed and unaligned multi-walled carbon nanotubes (MCNTs) infused liquid epoxy adhesive have been reported for significantly improving the adhesive-joint of carbon fiber reinforced polymer (CFRP) composite laminates. However, it has not been determined in the literature if the alignment of MCNTs would provide an additional improvement than the randomly aligned case. In this study, various epoxy film adhesives embedded with 1wt% through-thickness aligned MCNTs, unaligned MCNTs, aligned carbon nanofibers (CNFs), and unaligned CNFs were used for bonding CFRP laminates. These variants have been used to bond two CFRP laminates for the ASTM D5868-01 single lap test as well as a steel variant for the same bonding process. The average shear strengths of the samples bonded by the various film adhesives were compared with the samples bonded by the pure epoxy-films. Microscopic analysis has been used to examine the fracture surface after testing. It was also used to visualize how the film adhesives fail while experiencing shear. This study has investigated the effectiveness of infusing through-thickness directionally aligned vs. unaligned nanoparticles in an epoxy film adhesive for bonding CFRP laminates and steel plate. It also indicates the potential future research direction of using nanoparticles in advanced adhesive technologies.more » « less