The Influence of Thermomechanical Conditions on the Hot Ductility of Continuously Cast Microalloyed Steels.

Continuous casting is the most common method for producing steel into semi-finished shapes like billets or slabs. Throughout this process, steel experiences mechanical and thermal stresses, which influence its mechanical properties. During continuous casting, decreased formability in steel components leads to crack formation and failure.

Porosity evolution and oxide formation in bulk nanoporous copper dealloyed from a copper-manganese alloy studied by resistometry.

The synthesis of bulk nanoporous copper (npCu) from a copper-manganese alloy by electrochemical dealloying and free corrosion as well as the electrochemical behaviour of the dealloyed structures is investigated by resistometry. In comparison to the well-established nanoporous gold (npAu) system, npCu shows strongly suppressed reordering processes in the porous structure (behind the etch front), which can be attributed to pronounced manganese oxide formation. Characteristic variations with the electrolyte concentration and potential applied for dealloying could be observed.

Cavity Nucleation and Growth in Nickel-Based Alloys during Creep.

The number of fossil fueled power plants in electricity generation is still rising, making improvements to their efficiency essential. The development of new materials to withstand the higher service temperatures and pressures of newer, more efficient power plants is greatly aided by physics-based models, which can simulate the microstructural processes leading to their eventual failure. In this work, such a model is developed from classical nucleation theory and diffusion driven growth from vacancy condensation.

An In Situ Synchrotron Dilatometry and Atomistic Study of Martensite and Carbide Formation during Partitioning and Tempering.

Precipitation hardened and tempered martensitic-ferritic steels (TMFSs) are used in many areas of our daily lives as tools, components in power generation industries, or in the oil and gas (O&G) industry for creep and corrosion resistance. In addition to the metallurgical and forging processes, the unique properties of the materials in service are determined by the quality heat treatment (HT). By performing a quenching and partitioning HT during an in situ high energy synchrotron radiation experiment in a dilatometer, the evolution of retained austenite, martensite laths, dislocations, and carbides was characterized in detail.

Reuse of Ti6Al4V Powder and Its Impact on Surface Tension, Melt Pool Behavior and Mechanical Properties of Additively Manufactured Components.

The quality and characteristics of a powder in powder bed fusion processes play a vital role in the quality of additively manufactured components. Its characteristics may influence the process in various ways. This paper presents an investigation highlighting the influence of powder deterioration on the stability of a molten pool in a laser beam powder bed fusion (LB-PBF, selective laser melting) process and its consequences to the physical properties of the alloy, porosity of 3D-printed components and their mechanical properties.

Stability of a Melt Pool during 3D-Printing of an Unsupported Steel Component and Its Influence on Roughness.

The following work presents the results of an investigation of the cause-effect relationship between the stability of a melt pool and the roughness of an inclined, unsupported steel surface that was 3D-printed using the laser powder bed fusion (PBF-L/M) process. In order to observe the balling effect and decrease in surface quality, the samples were printed with no supporting structures placed on the downskin. The stability of the melt pool was investigated as a function of both the inclination angle and along the length of the melt pool.

Influence of Melt-Pool Stability in 3D Printing of NdFeB Magnets on Density and Magnetic Properties.

The current work presents the results of an investigation focused on the influence of process parameters on the melt-track stability and its consequence to the sample density printed out of NdFeB powder. Commercially available powder of Nd7.5Pr0.

In Situ Formation of TiB in Fe-B System with Titanium Addition and Its Influence on Phase Composition, Sintering Process and Mechanical Properties.

Interaction of iron and boron at elevated temperatures results in the formation of an E (Fe + FeB) eutectic phase that plays a great role in enhancing mass transport phenomena during thermal annealing and therefore in the densification of sintered compacts. When cooled down, this phase solidifies as interconnected hard and brittle material consisting of a continuous network of FeB borides formed at the grain boundaries. To increase ductile behaviour, a change in precipitates' stoichiometry was investigated by partially replacing iron borides by titanium borides.

Improving the Dimensional Stability and Mechanical Properties of AISI 316L + B Sinters by SiN Addition.

The following paper describes a new and effective method to obtain high-density sinters with simultaneously decreased distortions, produced by one press and sinter operation. This effect was achieved through the induced disappearance of the eutectic liquid phase. The study was carried out on AISI 316L stainless steel powder that was mixed with elemental boron and silicon nitride.

Effect of Process Parameters and High-Temperature Preheating on Residual Stress and Relative Density of Ti6Al4V Processed by Selective Laser Melting.

The aim of this study is to observe the effect of process parameters on residual stresses and relative density of Ti6Al4V samples produced by Selective Laser Melting. The investigated parameters were hatch laser power, hatch laser velocity, border laser velocity, high-temperature preheating and time delay. Residual stresses were evaluated by the bridge curvature method and relative density by the optical method.

Calculation of the Intermetallic Layer Thickness in Cold Metal Transfer Welding of Aluminum to Steel.

The intermetallic layer, which forms at the bonding interface in dissimilar welding of aluminum alloys to steel, is the most important characteristic feature influencing the mechanical properties of the joint. In this work, horizontal butt-welding of thin sheets of aluminum alloy EN AW-6014 T4 and galvanized mild steel DC04 was investigated. In order to predict the thickness of the intermetallic layer based on the main welding process parameters, a numerical model was created using the software package Visual-Environment.

Innovative surface modification of Ti6Al4V alloy by electron beam technique for biomedical application.

The low elastic modulus, high corrosion resistance and excellent biological response allow titanium alloys to be used for permanent orthopaedic devices. Furthermore, the design of specific multi scale surface topographies on titanium alloys can provide a fast osseointegration. This work highlights the use of electron beam as a promising technique to produce a designed surface topography and improve the tribological behaviour of Ti6Al4V alloy.

Failure modes for total ankle arthroplasty: a statistical analysis of the Norwegian Arthroplasty Register.

Background: It is imperative to understand the most common failure modes of total ankle arthroplasty (TAA) to appropriately allocate the resources, healthcare costs, enhancing surgical treatment methods, and improve design and longevity of the implant. The objective of this study was to investigate the primary mode or modes of failure (Loose talar component, loose tibial component, dislocation, instability, misalignment, deep infection, Fracture (near implant), Pain, defect polyethylene (PE), other, and missing information) of TAA implants, so these failure mode/modes can be targeted for future improvement.

Methods: The Norwegian Total Hip Arthroplasty Register 2008 was chosen as the primary source of data since the register have been in existence for 20 years and also gives more specific failure modes than other registries.