A5054582472- Microstructure and Mechanical Properties of Steels
- Advanced Materials Characterization Techniques
- Metal Alloys Wear and Properties
- Metal and Thin Film Mechanics
- Magnetic Properties and Applications
- Nuclear Materials and Properties
- Fusion materials and technologies
- Hydrogen embrittlement and corrosion behaviors in metals
- High Temperature Alloys and Creep
- Ion-surface interactions and analysis
- Advanced Welding Techniques Analysis
- Advanced materials and composites
- Microstructure and mechanical properties
- Semiconductor Quantum Structures and Devices
- Welding Techniques and Residual Stresses
- Diamond and Carbon-based Materials Research
- Silicon Nanostructures and Photoluminescence
- Additive Manufacturing Materials and Processes
- Intermetallics and Advanced Alloy Properties
- Silicon and Solar Cell Technologies
- GaN-based semiconductor devices and materials
- Radioactive element chemistry and processing
- Magnetic properties of thin films
- Semiconductor materials and devices
- ZnO doping and properties
University of Oxford
2022-2024
Montanuniversität Leoben
2009-2022
University of California, Berkeley
2014
Laser powder bed fusion (LPBF) facilitates economic advantages by enhancing cutting speeds of tools through the implementation complex internal cooling channels that could not be fabricated otherwise. However, tool steels are prone to cracking during cyclic remelting process with extremely fast rates due their high carbon and alloying element contents related stresses. In this work, a correlation between microscopic crack patterns in steel processed via LPBF, residual stress gradients, local...
High strength combined with excellent ductility can be achieved by quenching and partitioning (Q&P) microstructures containing martensite a considerable amount of retained austenite. Since the mechanical properties are inherited from microstructure, thorough understanding this relationship is indispensable. In present work, in-situ synchrotron X-ray diffraction was used to investigate transformation kinetics during Q&P processing. The effect different heat treatment conditions on...
Chromium alloys are being considered for next-generation concentrated solar power applications operating > 800 °C. Cr offers advantages in melting point, cost, and oxidation resistance. However, improvements mechanical performance needed. Here, Cr-based body-centred-cubic (bcc) of the type Cr(Fe)-NiAl investigated, leading to 'bcc-superalloys' comprising a bcc-Cr(Fe) matrix (β) strengthened by ordered-bcc NiAl intermetallic precipitates (β'), with iron additions tailor precipitate volume...
Within this work the effect of B content on microstructure, phase composition and mechanical properties CVD Ti(B,N) coatings is investigated. with contents from 0 (fcc-TiN) to ∼5, ∼15, ∼30, ∼45 66 (h-TiB2) at.% have been deposited by CVD. The elemental was confirmed ERDA their microstructure investigated using XRD SEM. With increasing content, a transition fcc h-dominated structure via dual-phase fcc/h-Ti(B,N) observed, which accompanied decreasing grain size µm nm range. Combinatorial use...
Abstract In the automotive industry resistance, spot welding is dominant technology in sheet metal joining of advanced high strength steels (AHSS). order to improve mechanical performance AHSS welds, in-process tempering via a second pulse possible approach. this work, two different double schemes were applied 1200 MPa transformation-induced plasticity (TRIP)-aided bainitic ferrite (TBF) steel. The microstructures welds characterized light optical and scanning electron microscopy....
The transformation-induced plasticity (TRIP)-effect is an efficient way to increase the formability in high performance steels. Hence, optimal stability of retained austenite crucial benefit most from this effect. In present work, in-situ energy X-ray diffraction was used study martensite transformation upon uniaxial tensile loading a TRIP-assisted steel produced by quenching and partitioning (Q&P) process. A detailed analysis patterns recorded during deformation allowed with respect applied...
The properties of the heat-affected zone (HAZ) are reported to have a great influence on mechanical performance resistance spot welded advanced high strength steels. Therefore, in present work, HAZ medium-Mn steel is characterized regarding its microstructure and depending distance fusion (FZ). In order obtain local HAZ, samples were heat-treated joule-heating thermal simulator using different peak temperatures physically simulate HAZ. By comparing hardness these within could be determined....
In the present work, influence of cooling time on mechanical performance, hardness, and microstructural features a double pulse resistance spot welded medium-Mn steel are investigated. Curves electrical throughout welding revealed that strongly influences heat generation during second pulse. A after short re-melts center, treats edge primary fusion zone. This desired in-process treatment leads to modification cast-like martensitic structure by recrystallization illustrated electron...
Abstract In the present work different approaches to improve mechanical properties of a resistance spot welded 1200 MPa transformation induced plasticity-aided bainitic ferrite steel are evaluated. An extension welding time results in coarsening microstructure outer fusion zone and maximum force derived by cross tension strength test did not significantly. A temper pulse after long cooling leads pronounced softening zone, as determined hardness mapping, which resulted enhanced weld...
Carbide‐free bainitic steels represent attractive candidates for the automotive industry to meet conflicting requirements of increasing safety and decreasing vehicle weight. Their fine‐grained multi‐phase microstructure enables a well‐balanced combination high strength ductility. To identify characterize all phases in dependence isothermal transformation temperature, metallographic high‐resolution techniques are applied. The stability individual is evaluated based on their C concentration...