Production and characterization of Cuzr-Re based bulk amorphous/nanocrystal composite

Download

index.pdf

Date

2017

Author

Sıkan, Fatih

Metadata

Show full item record

Item Usage Stats

306
views

120
downloads

Bulk metallic glasses have recently attracted much attention due to their high mechanical strength both in amorphous and in the amorphous/nanocrystal composite form along with their high glass forming ability. However, factors such as having a low plastic strain limit their potential application as structural materials. In this present work, ternary (Zr50Cu40Al10)100–xSmx (x:0-4 at. %) amorphous alloys were produced by melt-spinning in ribbon form and suction casting in bulk form within the diameter range of 1 to 3 millimeters. The amorphous and the devitrified states of these alloys were investigated with scanning electron microscopy (SEM), transmission electron microscopy (TEM), X-ray diffraction (XRD) and scanning differential calorimetry (DSC), Atom Probe Tomography (APT) techniques. Mechanical behavior of these alloys were investigated using compression and hardness testing. Failure modes and structures were analyzed using SEM as well. Furthermore, micro-mechanical testing experiments were conducted in order to get insights on the mechanical behavior of amorphous and partially crystalline specimens in nano and micro scale. Sm addition up to 4 at. % lead to nanocrystallization of approximately 5-10 nm spherical Cu2Sm phase for (Zr50Cu40Al10)96Sm4 alloy. Further growth of Cu2Sm phase was thought to be hindered due to solute pile-up of Zr atoms at phase boundary and insufficiency of Sm atoms in amorphous phase. Since the amount of Sm atoms in amorphous matrix can be controlled by adjusting Sm content during alloying, nanocrystal size can be adjustable for such systems. Precipitation of Cu2Sm nanocrystals were found to increase strength and hardness of (Zr50Cu40Al10)96Sm4 alloy; however, caused a significant embrittlement problem. Adjusting size and distributions of these nanocrystals may prove useful in eliminating this embrittlement problem. This study demonstrates how complex microstructures can be formed in a metallic glass to make a composite structure during devitrification and how these structures can be tuned for better properties.

Subject Keywords

Nanocrystals., Microalloying., Metallic glasses., Amorphous substances.

URI

http://etd.lib.metu.edu.tr/upload/12621239/index.pdf
https://hdl.handle.net/11511/26910

Collections

Graduate School of Natural and Applied Sciences, Thesis

Suggestions

OpenMETU
Core

Synthesis and characterization of Ti-based bulk amorphous/naocrystalline alloys for engineering applications Abdelal, Ali; Akdeniz, Mahmut Vedat; Department of Metallurgical and Materials Engineering (2004) Amorphous and bulk amorphous metallic alloys are an intriguing class of structural materials and possess a range of interesting properties, including near theoretical strength, high hardness, extremely low damping characteristics, excellent wear properties, high corrosion resistance, low shrinkage during cooling and almost perfect as-cast surfaces with good potential for forming and shaping. In this study, new Ti-based bulk amorphous alloys are tried to be modeled and synthesized. For that purpose, electron...
Bulk amorphous/nanocrystalline materials: structural amorphous steels / Yağmurlu, Bengi; Akdeniz, Mahmut Vedat; Mekhrabov, Amdulla O.; Department of Metallurgical and Materials Engineering (2014) Although conventional steels with crystalline structures have been extensively utilized by industries, bulk amorphous steels (BASs) show great potential to supersede these crystalline steels for some critical structural and functional applications because of their unusual combinations of engineering properties: these include higher strength and hardness, better wear and corrosion resistance. Moreover, compared with most other bulk amorphous alloy systems such as Zr- and Pd-based bulk metallic glasses, BASs ...
Development of Nanostructured Metallic Glasses with High Toughness Bagheri Behboud, Ali; Özerinç, Sezer; Department of Mechanical Engineering (2021-8) Metallic glasses are metallic alloys with disordered atomic structures and desirable mechanical properties such as high hardness, high elastic limits, and wear resistance. These properties make metallic glasses promising materials for wear-resistant, corrosion-resistant, and biocompatible coating applications. On the other hand, metallic glasses are brittle, which is a major disadvantage for their use in practice. This thesis study aimed to tackle this problem through the development of nanostructured metal...
Synthesis and characterization of copper based bulk amorphous alloys Erdem, Mermer; Akdeniz, Mahmut Vedat; Mekhrabov, Amdulla O.; Department of Metallurgical and Materials Engineering (2013) Copper based bulk metallic glasses (BMG’s) are one of the promising advanced materials due to their unique mechanical properties, high glass forming ability (GFA) and low cost. In this thesis, the aim is to synthesize Cu-Hf based BMG’s and to investigate the crystallization behavior. Moreover, the crystallization kinetics by means of activation energies, critical cooling rate, nanocrystallization and Avrami exponents have been studied. Cu70Hf30 and Cu50Hf50 binary alloys were produced via arc melting with s...
Synthesis and Characterization of Zirconium based Bulk Amorphous Alloys Saltoğlu, İlkay; Akdeniz, Mahmut Vedat; Mehrabov, Amdulla (2005-09-28) In recent years, bulk amorphous alloys and nanocrystalline materials have been synthesized in a number of ferrous and non-ferrous based alloys systems, which have gained some applications due to their unique physico-chemical and mechanical properties. In the last decade, Zr-based alloys with a wide supercooled liquid region and excellent glass forming ability have been discovered. These systems have promising application fields due to their mechanical properties; high tensile strength, high fracture toughne...

Citation Formats

F. Sıkan, “Production and characterization of Cuzr-Re based bulk amorphous/nanocrystal composite,” M.S. - Master of Science, Middle East Technical University, 2017.