A5028555244- Intermetallics and Advanced Alloy Properties
- Concrete and Cement Materials Research
- Semiconductor materials and interfaces
- Metallurgical and Alloy Processes
- MXene and MAX Phase Materials
- Nuclear materials and radiation effects
- High Entropy Alloys Studies
- Recycling and utilization of industrial and municipal waste in materials production
- Magnesium Oxide Properties and Applications
- Metal and Thin Film Mechanics
- Titanium Alloys Microstructure and Properties
- Advanced ceramic materials synthesis
- Additive Manufacturing Materials and Processes
- Metal Alloys Wear and Properties
- Radioactive element chemistry and processing
- Nuclear Materials and Properties
- Innovative concrete reinforcement materials
- Boron and Carbon Nanomaterials Research
- High-Temperature Coating Behaviors
- Concrete Properties and Behavior
- Advanced materials and composites
- Corrosion Behavior and Inhibition
- High Temperature Alloys and Creep
- Material Properties and Applications
- Bauxite Residue and Utilization
University of Sheffield
2014-2025
Materials Science & Engineering
2012
The bulk of the cement industry's environmental burden is from calcareous source. Calcium mostly available naturally as limestone (CaCO3), where almost half mass eventually released CO2 during clinker manufacture. Iron (Fe) fourth most common element in Earth's crust surpassed only by oxygen, silicon, and aluminium; therefore, potential raw materials for alternative cements can contain significant amounts iron. This review paper discusses detail abundantly Fe-rich natural resources...
AbrstractThe present study is part of a wider investigation to develop an alternative cementing system for the encapsulation problematic low and intermediate level radioactive waste. It has been suggested that systems, with lower internal pH than conventional Portland cement based composite cements, may reduce corrosion some reactive metals be beneficial long term durability wasteforms. A potential acid–base system, on mixing calcium aluminate (CAC) acidic phosphate solutions. Although these...
Nb-silicide based alloys could be used at T > 1423 K in future aero-engines. Titanium is an important additive to these new where it improves oxidation, fracture toughness and reduces density. The microstructures of the consist Nb solid solution, silicides other intermetallics can present. Three Nb5Si3 polymorphs are known, namely αNb5Si3 (tI32 Cr5B3-type, D8l), βNb5Si3 W5Si3-type, D8m) γNb5Si3 (hP16 Mn5Si3-type, D88). In 5-3 atoms substituted by Ti atoms. type stable depends on temperature...
In Nb-silicide based alloys Al, Cr, Hf, and Ti additions are crucial for achieving balance of properties. It is not known how the simultaneous addition Hf with Al Ti, or affects macrosegregation, alloying hardness, Young’s modulus bulk alloy oxidation, contamination solid solution Nbss Nb5Si3 compound by oxygen. Two nominal compositions (at.%) Nb-24Ti-18Si-5Al-5Hf (alloy NbSiTiHf-5Al) Nb-24Ti-18Si-5Al-5Cr-5Hf NbSiTiHf-5Al-5Cr) were studied in as-cast heat-treated conditions after isothermal...
High-entropy and multicomponent alloys are believed to offer opportunities for improved properties currently of great interest the research community. Studies on these materials largely conducted small samples, but, many practical applications, larger-scale processing would be needed. The metallic parts high dimensionality conventionally begins with casting, but an increase in scale melt increases potential effects dependent segregation, diffusion thermal transport. objective here is...
Alloying with Al, Cr, Sn, and Ti significantly improves the oxidation of Nb silicide-based alloys at intermediate high temperatures. There is no agreement about what concentration Sn in should be. It has been suggested that ≤ 3 at.% improved formation brittle A15-Nb3Sn compound suppressed. Definite improvements behaviour have observed 5 or even higher concentrations, up to 8 Sn. The research reported this paper three model low nominal compositions Nb-24Ti-18Si-5Cr-2Sn (ZX3),...
Nb–silicide based alloy will require some kind of coating system. Alumina forming alloys that are chemically compatible with the substrate could be components such systems. The intermetallic Nb1.7Si2.4Ti2.4Al3Hf0.5 and Nb1.3Si2.4Ti2.4Al3.5Hf0.4 were studied in cast, heat treated isothermally oxidised conditions at 800 1200 °C to find out if they alumina scale formers. designed using design methodology NICE required (i) not have stable solid solution phase their microstructures; (ii) pest...
The paper presents the results of an experimental study large (≈0.6 kg) arc melted buttons four Ti free Nb-silicide based alloys with Sn addition nominal compositions (at.%) Nb-18Si-5Hf-5Sn (EZ1), Nb-18Si-5Al-5Sn (EZ7), Nb-18Si-5Cr-5Hf-5Sn (EZ3) and Nb-18Si-5Al-5Hf-5Sn (EZ4). were studied in as-cast heat treated conditions. In all there was macrosegregation Si (MACSi). Among single element additions Hf had weakest strongest effect on MACSi. simultaneous presence Cr alloy EZ3 βNb5Si3 primary...
In this paper two Nb-silicide-based alloys with nominal compositions (at.%) Nb-12Ti-18Si-6Ta-2.5W-1Hf-2Sn-2Ge (JZ1) and Nb-12Ti-18Si-6Ta-2.5W-1Hf-5Sn-5Ge (JZ2) were studied. The designed using the alloy design methodology NICE to meet specific research objectives. cast microstructures of both sensitive solidification conditions. There was macro-segregation Si in JZ1 JZ2. βNb5Si3 primary phase Nbss stable. A15-Nb3X (X = Ge,Si,Sn) stable only Nbss+βNb5Si3 eutectic not as Nb3Si silicide that...
This paper presents the results of a systematic study Nb-24Ti-18Si based alloys with 5 at.% Sn addition. Three nominal compositions (at.%), namely Nb-24Ti-18Si-5Cr-5Sn (ZX4), Nb-24Ti-18Si-5Al-5Sn (ZX6), and Nb-24Ti-18Si-5Al-5Cr-5Sn (ZX8), were studied to understand how increased concentration improved oxidation resistance. In all three there was macrosegregation, which most severe in ZX8 primary βNb5Si3 transformed completely αNb5Si3 after heat treatment. The Nbss not stable ZX6, Nb3Sn...
Abstract Vitrification is used for the immobilization and conditioning of high-level waste (HLW) arising from reprocessing spent nuclear fuel in UK. also under consideration certain intermediate-level wastes (ILW), where there may be advantages volume reduction removal uncertainties long-term behaviour, compared to encapsulation a cement grout. This paper gives an overview recent work into chemical durability UK vitrified wasteforms inform technical specification disposal facilities these...
The use of modeling tools can signifcantly speed up the adoption sustainable construction materials.
Coating system(s) will be required for Nb-silicide based alloys. Alumina forming alloys that are chemically compatible with the alloy substrate could components of such systems. The intermetallic Nb1.45Si2.7Ti2.25Al3.25Hf0.35 (MG5) and Nb1.35Si2.3Ti2.3Al3.7Hf0.35 (MG6) were studied in cast, heat treated isothermally oxidised conditions at 800 1200 °C to find out if they αAl2O3 scale formers. A (Al/Si)alloy versus Nb/(Ti + Hf)alloy map, which can considered a map Multi-Principle Element or...
Isothermal conduction calorimetry has been used to monitor the early hydration of Portland–blastfurnace slag (BFS)‐blended cements. Portland:BFS composite cements with ordinary Portland cement replacements from 0 90 wt% were studied at curing temperatures 12° 90°C. Peak II, principally associated alite (Ca 3 SiO 5 ) hydration, was accelerated increasing temperature for all blends. S, BFS particularly noticeable 40° and 60°C. At higher temperatures, peak S merged indicating thermal activation...