Nanocomposites VI: Nanoscience and Nanotechnology in Advanced Composites: Microstructure and Properties of Nanocomposites
Sponsored by: TMS Structural Materials Division, TMS: Composite Materials Committee
Program Organizers: Srivatsan Tirumalai; Manoj Gupta, National University of Singapore
Wednesday 2:00 PM
February 26, 2020
Room: Solana
Location: Marriott Marquis Hotel
Session Chair: Manoj Gupta, National University of Singapore
2:00 PM Invited
On the Role of Processing on Microstructural Development and Mechanical Response of Magnesium-based Nanocomposites: Sankaranarayanan Seetharaman1; Jayalakshmi Subramanian2; Arvind Singh2; Srivatsan Tirumalai. S.3; Manoj Gupta4; 1Ansys Inc; 2Wenzhou University; 3The University of Akron; 4National University of Singapore
In this presentation an attempt will be made to both elucidate and highlight the intricacies specific to magnesium-based composites containing nano-sized particulates of boron nitride [BN]. The composite materials were engineered using the techniques of solid-state processing and liquid state processing. The solid-state processing method was based on powder metallurgy approach and involved use of the technique of microwave assisted bidirectional sintering. The liquid state processing method involved the technique of disintegrated melt deposition [DMD], which combines the benefits provided by stir casting, bottom pouring and spray deposition. The composite materials in the as-synthesized condition were then extruded. Samples of the as-extruded composites were characterized for their microstructure and basic mechanical properties to include hardness and tensile properties. The influence of processing technique used on microstructural development and resultant mechanical properties of the engineered composites will be highlighted.
2:30 PM Invited
The Mechanical and Thermal Response of Shape Memory Alloy-reinforced Aluminum Nanocomposites: Penchal Reddy Matli1; Vyasaraj Manakari1; Gururaj Parande1; RA Shakoor2; T. S. Srivatsan3; Manoj Gupta1; 1National University of Singapore; 2Qatar University; 3The University of Akron
The concept of developing intelligent materials that has the innate capability of healing its damage has drawn increased interest due to its potential for selection and use in both the automobile sector and the aerospace sector. In this presentation, a shape memory alloy [Ni50Ti50 (NiTi)]-reinforced aluminum matrix nanocomposites were fabricated using the technique of powder metallurgy followed by hybrid microwave sintering. The influence of the addition of nanosized NiTi alloy particles on microstructural, thermal and mechanical properties of aluminum were examined. With the addition of NiTi alloy, a noticeable improvement in hardness, ultimate compression/tensile strength and yield strength were observed, with a concurrent decrease in the values of failure strain and coefficient of thermal expansion (CTE). The observed increase in properties of the engineered nanocomposite as a consequence of contributions from intrinsic microstructural effects will be presented and discussed.
3:00 PM
Electrical Performance of Bulk Al-ZrB2 Nanocomposites from 2K to 300K: Shuaihang Pan1; Gongcheng Yao1; Jie Yuan1; Xiaochun Li1; 1University of California-Los Angeles
Electrical properties are of significance for metals/alloys. While nanoparticles can enhance mechanical performance of metals/alloys, there is a strong need to understand how nanoparticles affect their electric behavior at various temperatures. In the study, ZrB2 nanoparticles were synthesized in situ to cast bulk Al-ZrB2 samples for electric characterizations. The electrical conductivity, electron mobility, and electron concentration of Al-3 vol% ZrB2 were measured in the temperature range from 2K to 300K. With a consideration to its compositions, morphologies, grain sizes, and nanophase sizes, the effects of in-situ ZrB2 nanoparticles on the Al matrix were systematically studied. It is discovered the Al-ZrB2 interfaces play a key role by tuning structural and electrical performances. This mechanism is important to better understand the electron behaviors in in-situ Al-matrix nanocomposites. The in-situ fabrication and electrical characterization methods can be readily applied to other metallic nanocomposites.
3:25 PM Break
3:45 PM Invited
Bioresorbable Nano Hydroxyapatite Reinforced Magnesium Alloplastic Bone Substitute for Biomedical Applications: A Study: Somasundaram Prasadh1; Vyasaraj Manakari1; Gururaj Parande1; Srivatsan Tirumalai2; Raymond Wong1; Manoj Gupta1; 1National University of Singapore; 2The University of Akron
Combining the mechanical, biological and corrosion properties of magnesium can enable it to perform as a biocompatible and degradable implant for load-bearing applications. Accordingly, the present study focuses on determining the influence of Hydroxyapatite nanoparticles on mechanical strength, immersion resistance and cytocompatibility properties of magnesium processed by the powder metallurgy technique. In-vitro cytotoxicity and cell proliferation were done using LDH enzyme release assay and MTS assay. The in vitro biocompatibility and cell viability were determined by attachment of a direct cell to the samples. The addition of nano hydroxyapatite to pure magnesium did not alter the cytocompatibility of the composite. With the addition of 0.5 pct. nano hydroxyapatite to magnesium, the MC3T3-E1 cells revealed significant cell growth. Among the samples tested, cell viability data revealed that the 0.5 pct. hydroxyapatite exhibited the lowest cytotoxicity coupled with increased cell viability. The LDH enzyme release assay results revealed the MC3T3-E1 cells cultured in the presence of low and high concentrations of nano hydroxyapatite for 24 hours to support the cytocompatibility of the synthesized composite. No observable toxic effects were evident, which is consistent with the enhanced corrosion resistance of magnesium alloys resulting in better cell attachment and more cell viability. The inclusion of nanosized reinforcements restricted the growth of grains for magnesium while concurrently enhancing both the compression and biological properties. The immersion tests revealed controlled weight loss for the Mg-0.5 vol.% nano hydroxyapatite composite.
4:15 PM Cancelled
Hierarchical 3D Nanolayered Duplex-phase Zr with High Strength, Strain Hardening, and Ductility: Jie-Wen Zhang1; Wei-Zhong Han1; 1Xi’an Jiaotong University
Nanolayered, bimetallic composites are highly anisotropic, resulting in limited strain hardening and ductility, due to their 2D planar, unidirectional arrangement. Here we present a novel hierarchical microstructure, comprised of crystals consisting of 3D nanolayered α/β-Zr networks. By direct comparison with coarse-layered material of the same chemistry, the unusual hierarchical 3D structure gives rise to high strength, strain hardening and ductility. Using TEM analysis and hysteresis testing, we discovered that the 3D randomly oriented biphase boundaries result in progressively dispersive rather than localized slip with increasing strain. Dislocation activity in the α-Zr lamellae transitions from single slip to multislip and eventually to multimodal slip as strain increases. The diffusive slip-promoting properties of 3D layered networks can potentially invoke simultaneous high strength, strain hardening, and ductility, and reveal a new target in the microstructural design of high performance structural materials.