October_2021_AMP_Digital

A D V A N C E D M A T E R I A L S & P R O C E S S E S | O C T O B E R 2 0 2 1 1 1 PROCESS TECHNOLOGY SMART TECH BREAKTHROUGH A new polymerization technique to simultaneously cure and vascularize high-performance materials in a mat- ter of minutes, instead of days, was de- veloped by researchers at the Universi- ty of Colorado, Fort Collins. Inspired by biological systems like human blood vessels or plant leaves, the scientists created microchannels inside structur- al polymers and composites, impart- ing multifunctional properties to the host structure such as self-healing and thermal regulation. The research break- through shortens themanufacturing cy- cle from two days of processing under a vacuum at high temperatures to five minutes at room temperature and am- bient pressure—without any resources like ovens or pumps. Internally created heat from fron- it is more favorable to be in the keyhole domain—at a similar concentration of defects—than in the lack of fusion do- main. The teamalso discovered that mi- crostructural refinement around a key- hole defect can counteract the weak- ening effect of the defect. Even up to 4-5%porosity in the keyhole domain re- sults in the same yield strength as a part with negligible porosity, a target metric many mechanical engineers use to de- sign parts. “We modified the laser processing conditions to simulate natural faults in the process and generated three sim- ilar amounts of defects in the keyhole and lack of fusion domains,” explain the scientists. “Then, we scanned and quantified material from each process- ing condition using x-ray computed to- mography to map the defect size and distribution, comparing samples con- taining these resultant defects in mono- tonic tension testing to determine the preferred defect domain for a given amount of defects.” “This work is a critical step in lay- ing the foundation to enable qualifica- tion of AM parts in the future,” the re- searchers say. “A general understand- ing of the influence of the effects of processing conditions on the resulting microstructure and properties of a ma- terial and component will provide the scientific basis to enable protocols for safe implementation of additively man- ufactured parts.” jhu.edu. Manufacturing process of a vascularized structure using a 3D-printed template that mimics vascular networks of a leaf. Courtesy of Mayank Garg. Pennex Aluminum, Wellsville, Pa., completed a $23 million expansion of their Leetonia, Ohio, facility and plans to hire 70 new employees by year’s end. The company specializes in aluminum fabrication and extrusions for the automotive, construction, HVAC, landscaping, and off-road vehicle markets. pennexaluminum.com. BRIEFS Service Heat Treating, Milwaukee, recently finalized a multiyear plant expansion of nearly 40,000 sq ft, doubling its space. The company also added another batch furnace and four new nitriding furnaces. serviceht.com. Taylor Bean is a new saw operator at Pennex Aluminum, Leetonia, Ohio. tal polymerization solidifies the host while deconstructing the template into gas, leaving behind a vascular network. Combining the two steps into one elimi- nates the need for an oven and provides greater control to engineers and scien- tists to explore advanced biological functions and more complex systems. The discovery paves a new future for efficient smart technology, impacting the aerospace, wind, and automotive sectors. Such industries are increasing- ly using composite materials in struc- tural parts due to their low density, ex- cellent mechanical properties, and cor- rosion resistance. However, composites are prone to internal damages that are not easy to detect. Using vascularized structures al- lows for delivering beneficial fluids to the damaged site for healing. Accord- ing to the researchers, these self-heal- ing features will enhance the reliability and longevity of structural composites. colostate.edu . UTILIZING DEFECTS Scientists at the Johns Hopkins Applied Physics Laboratory, Laurel, Md., areworking to gain a better understand- ing of different defects and their influ- ence on the mechanical performance of additive manufacturing (AM) materi- als. The researchers deliberately intro- duced the two natural types of process- ing defects, lack of fusion and keyhole, into samples to determine how they in- fluence parts’ mechanical properties. Results showed that while high amounts of eachdefect are unfavorable,