Nanocomposites VI: Nanoscience and Nanotechnology in Advanced Composites: Processing and Fabrication of Nanocomposites
Sponsored by: TMS Structural Materials Division, TMS: Composite Materials Committee
Program Organizers: Srivatsan Tirumalai; Manoj Gupta, National University of Singapore
Wednesday 8:30 AM
February 26, 2020
Room: Solana
Location: Marriott Marquis Hotel
Session Chair: Srivatsan Tirumalai
8:30 AM Invited
Processing, Properties and Potential Applications of Magnesium Alloy-based Nanocomposites: A Review: Sravya Tekumalla1; Manoj Gupta1; 1National University of Singapore
Strong, ductile, lightweight, biocompatible and non-toxic materials are the need of the hour for metal based industries such as aerospace, automotive, electronics and biomedical sectors. Magnesium based materials, due to their lightweight, excellent dimensional stability and mechanical integrity, have a tremendous potential to replace the existing commercial Al, Ti alloys and steels currently being used. Due to these attractive qualities of magnesium, there has been a spurt in the quest of a variety of magnesium materials targeting different functionalities. One subset of magnesium based materials are magnesium alloy-based nanocomposites that exhibit advantages of both magnesium alloys as well as magnesium nanocomposites. There has been advancement in this field through careful selection of alloying elements and reinforcement and optimization to obtain the best combination of properties. Accordingly, this paper will focus on the recent developments of magnesium alloy based nanocomposites capable of replacing conventional materials in multiple engineering and biomedical applications.
9:00 AM
Nanoparticle-enabled Phase Modification (Nano-Treating) of CuZrSi Pseudo-binary Alloy: Gongcheng Yao1; Shuihang Pan1; Chezheng Cao1; Maximilian Sokoluk1; Xiaochun Li1; 1University of California Los Angeles
Effectively modifying the faceted-growth phases in alloys has been a long-standing goal to improve the material properties. While traditional methods to tune the phase microstructures have reached a certain limit, dispersed nanoparticles in molten alloys are expected to effectively control the morphologies of phases. Here we report that Cu/WC nanocomposite masters, which can be readily used to process alloys, were fabricated. 1 vol.% and 4 vol.% WC nanoparticles were incorporated into a Cu-ZrCuSi pseudo-binary alloy, respectively. Results showed significant morphology modification and refinement of the CuZrSi phase upon addition of WC nanoparticles. It is inferred that heterogeneous nucleation and growth restriction of the ZrCuSi phase induced by WC nanoparticles are responsible for the morphological change. Hardness of the CuZrSi alloy with 4 vol.% WC increased by 43.4% compared to the base alloy. This novel yet simple route, nano-treating, has a tremendous potential for modifying alloys to achieve better performances.
9:25 AM
In-situ Mechanical Tests of Aluminum-carbon Nanotubes Composite Under Transmission Electron Microscopy: Kangpyo So1; Michael Short1; Ju Li1; Sidney Yip1; 1Massachusetts Institute of Technology
One-dimensional carbon nanotubes (CNT), which are mechanically strong and flexible, enhance the strength of the host metal matrix. However, the underlying strengthening/fracturing mechanism at the nanoscale is not clear. Here, we report a numerical analysis of the strengthening mechanism of CNT in aluminum along with the in-situ experimental observation. Nanoscale plasticity and rupturing processes near CNTs were observed by in-situ mechanical tests inside a Transmission Electron Microscope (TEM). The fracturing entails notch evoluation, surface strain, atomic sliding, dislocation gliding/climbing and local shear response. The notch in nanoscale was pinned due to the high mechanical strength of CNT. Further molercular details of 1D nano-dispersion hardening due to CNTs will be discussed.
9:50 AM Break
10:10 AM
Nanolayered Metallic Glass-crystalline Composites with High Strength and Wear Resistance: Sezer Ozerinc1; 1Middle East Technical University
Nanolayered metallic glass-crystalline composites are promising materials that combine the high strength of metallic glasses with the superior ductility of crystalline metals. Previous work has focused on metallic glass-FCC crystalline nanolayers, and showed that the strength follows the Hall-Petch behavior of increasing strength with decreasing layer thickness. In our work, we investigated metallic glass-HCP crystalline nanolayers. Interestingly, the strength of these layers does not show any size effect; strength is virtually constant for different layer thicknesses. The results can be explained by the high strength of HCP layers, exceeding that of the metallic glass. The unique size-independent strength of metallic glass-HCP nanolayers provide an effective way of understanding the sliding wear behavior of nanolayered composites. In this context, we investigated CuZr/Zr nanolayers, and observed decreasing wear resistance with decreasing layer thickness. This somewhat unusual trend can be explained by the low shear strength of the crystalline-amorphous interface.
10:35 AM
Facile Low-temperature Sintering of Nano-bio-ceramic Composite with 2D Reinforcement: Muhmood ul Hassan1; Ahmad Raza1; S.C. Yoo1; Ho Jin Ryu1; 1Kaist
Hydroxyapatite (HAp) and its composites are well known for their biocompatibility and recommended as bone implant and grafts. The nanoscale grain size is considered vital for higher bioactivity and cell-adhesion. The HAp-based monoliths are produced, conventionally, at higher sintering temperatures (≥ 900 °C), which has the challenges of increased grain-growth as well as decomposition to unwanted phases. This study demonstrated, for the first time, the low-temperature sintering of the hydroxyapatite-boron nitride nanoplates (HAp-BNNP) composite. The composite was cold-sintered at 200°C for 10 min without any additives. The sintered samples consist of nano-sized grains (10-20 nm) with the excellent interface between the matrix and 2D reinforcement. The nano-composite achieved 3.5 GPa micro-hardness with Young’s modulus of 65 GPa. The measured physical properties were comparable to high temperature sintered HAp. The composite showed good cell-adhesion and improved bioactivity, without having severe grain growth and changes in the stoichiometry.