Stable, Ductile and Strong Ultrafine HT-9 Steels via Large Strain Machining

2021-10-01
El-Atwani, Osman
Kim, Hyosim
Gigax, Jonathan G.
Harvey, Cayla
Aytuna, Berk
Efe, Mert
Maloy, Stuart A.
Beyond the current commercial materials, refining the grain size is among the proposed strategies to manufacture resilient materials for industrial applications demanding high resistance to severe environments. Here, large strain machining (LSM) was used to manufacture nanostructured HT-9 steel with enhanced thermal stability, mechanical properties, and ductility. Nanocrystalline HT-9 steels with different aspect rations are achieved. In-situ transmission electron microscopy annealing experiments demonstrated that the nanocrystalline grains have excellent thermal stability up to 700 & DEG;C with no additional elemental segregation on the grain boundaries other than the initial carbides, attributing the thermal stability of the LSM materials to the low dislocation densities and strains in the final microstructure. Nano-indentation and micro-tensile testing performed on the LSM material pre- and post-annealing demonstrated the possibility of tuning the material's strength and ductility. The results expound on the possibility of manufacturing controlled nanocrystalline materials via a scalable and cost-effective method, albeit with additional fundamental understanding of the resultant morphology dependence on the LSM conditions.
NANOMATERIALS

Suggestions

Experimental and analytical investigation of cold-formed steel floor trusses under gravity loading
Dizdar, Çağan; Baran, Eray; Department of Civil Engineering (2017)
Cold-Formed Steel structures are getting increasingly popular in the market with their economic and short construction duration advantages. One of the most common floor system used in CFS buildings utilizes trusses made of CFS members. Despite their increasing use, behavior of CFS floor trusses has been the subject of very limited research. The governing failure mode of these structures under gravity loading is usually local buckling of compression chord elements. Therefore, a reliable design of such struct...
Multilayer graphene growth on polar dielectric substrates using chemical vapour deposition
KARAMAT, SHUMAİLA; Celik, K.; Zaman, S. Shah; Oral, Ahmet (Elsevier BV, 2018-06-01)
High quality of graphene is necessary for its applications at industrial scale production. The most convenient way is its direct growth on dielectrics which avoid the transfer route of graphene from metal to dielectric substrate usually followed by graphene community. The choice of a suitable dielectric for the gate material which can replace silicon dioxide (SiO2) is in high demand. Various properties like permittivity, thermodynamic stability, film morphology, interface quality, bandgap and band alignment...
Nonlinear behaviour and stress concentrations in natural fiber composites under transverse loading
Çakmakçı, Onur; Kadıoğlu, Fevzi Suat; Sabuncuoğlu, Barış; Department of Mechanical Engineering (2019)
Natural fiber reinforced polymer composite materials attracted attention of the researchers recently. Some of them, especially flax fiber composites, do have quite favorable mechanical properties compared to synthetic fibers like E-glass. In this study, micromechanical model of flax fiber reinforced composite under transverse loading is investigated and compared with conventional synthetic fibers. The study includes variety of strains and response of the material under large deformations. Finite element mod...
Nanostructured poly(lactic acid)/soy protein/HPMC films by electrospinning for potential applications in food industry
Aydogdu, Ayca; Yıldız, Eda; Ayhan, Zehra; Aydoğdu, Yıldırım; Şümnü, Servet Gülüm; Şahin, Serpil (2019-03-01)
As an alternative to oil based materials, there is a demand for easily degradable packaging materials. With this regard, the objective of this study is to produce bilayer nanofiber sheets composed of Poly (lactic acid) (PLA) and soy protein, hydroxypropyl methylcellulose (HPMC) and combination of them by using electrospinning. In addition, it was aimed to analyze morphological, optical, thermal properties of films and investigate permeability characteristics. Homogenous nanofibers were successfully collecte...
Stability of double emulsions for food applications
Yıldırım, Merve; Şümnü, Servet Gülüm; Şahin, Serpil; Department of Food Engineering (2015)
Double emulsion technology has potential effect on development of diversity and quality of functional foods by decreasing the oil and salt concentration, encapsulating and controlled release of valuable components. In this study, it was aimed to formulate stable double emulsions to be used for reduction of oil content of mayonnaise samples. W1/O ratios of primary emulsions, stabilized by polyglycerol polyricinoleate, were designed as 2:8, and 4:6, and (W1/O)/W2 ratios of double emulsions were 2:8, and 4:6. ...
Citation Formats
O. El-Atwani et al., “Stable, Ductile and Strong Ultrafine HT-9 Steels via Large Strain Machining,” NANOMATERIALS, vol. 11, no. 10, pp. 0–0, 2021, Accessed: 00, 2021. [Online]. Available: https://hdl.handle.net/11511/94529.