Hot deformation is an effective way to tackle major problems in powder metallurgy, i.e., inferior mechanical properties and low relative density. To characterize the hot deformation behavior of NiAl-based alloy manufactured by hot pressing sintering, the isothermal compression tests were performed in the deformation temperature range of 1100–1300 °C with strain rate of 0.001–1 s−1. The result indicates that calculated hot activation energy Q is 326.31 kJ/mol. The processing efficiency maps and instability maps of NiAl-based alloy were established to optimize deformation parameters on the basis of dynamic material model. They were validated through microstructure evolution. The microstructure observation revealed that fine grains, dislocation pile-up, cracks appear in high efficiency, low efficiency, and instability domains, respectively. According to effective processing window revealed by processing maps, hot forging of sintered billets was performed. The elevated temperature elongation increases from 17.86% to 74.87% after forging. The stripping feature is found on fracture surface after forging.

This work studies the change microstructural and mechanical properties of biomedical component hot forging of titanium; was assessed quantitatively and qualitatively the microstructural features obtained in this titanium biocompatible Ti6Al4V. The forging process was obtained at temperature of 950 °C, after by technical optical microscopy are obtained the microstructural characterization showing the phases present after forging. Likewise, the technical X-ray diffraction (XRD) shows the presence of the phases. Also is evaluated the hardness and modulus of elasticity by technical nanoindentation. The characterization of this material has the objective to show that the results obtained with temperature study of 950 °C. Likewise by the forging process obtained a type phases and optimal properties required for these biomedical materials.

The Department of Materials and Metallurgical Engineering faculty at the South Dakota School of Mines and Technology (SDSM&T) has developed a unique undergraduate program that integrates research, extracurricular activities, and outreach experiences. A common thread throughout the program is an introduction to the artistic and historical background of metallurgical engineering. These activities use kinesthetic learning to promote student learning of metallurgical engineering, aspects often not traditionally included in engineering curricula. These programs are similar to those envisioned by the National Academy of Engineering in response to the changing needs of engineering. These are described in two visionary books published by the National Research Council.

A major focus of the program integrates blacksmithing activities with curricular, extracurricular, and outreach activities. All SDSM&T students are invited to a weekly blacksmithing activity called Hammer-in. Blacksmithing-related laboratories were added to the curriculum. Additionally, students developed a portable blacksmithing laboratory with faculty supervision. The laboratory has been taken to K-12 schools, including Native American schools on reservations, to reach out to regional students, thereby promoting interest in STEM careers. The success of these activities led to their incorporation into a National Science Foundation Research Experience for Undergraduate (REU) at SDSM&T called Back to the Future that focuses on understanding new technologies through historical antecedents. The SDSM&T students who participated in this REU used this experience as part of their junior/senior design courses. This program has increased enrollment in the department and has led to better learning outcomes for the students.

The trend to manufacture components reduced in size at the micro- and nano-scale is obvious and is becoming more and more the state of art in designing actuators, sensors and chips. In recent years, nanoscale fabrication has developed considerably, but the fabrication of freestanding nanosize components is still a great challenge. The fabrication of metallic nanocomponents utilizing three basic steps is demonstrated here. First, metallic alloys are used as factories to produce a metallic raw stock of nano-objects/nanoparticles in large numbers. These objects are then isolated from the powder containing thousands of such objects inside a scanning electron microscope using manipulators, and placed on a micro-anvil or a die. Finally, the shape of the individual nano-object is changed by nanoforging using a microhammer to get specific geometries such as discs and more complex components such as gears and wheels in the near future. The almost cubic particles are essentially defect-free, therefore, provide very high strength (σ>2500MPa) in combination with excellent formability (|ϕ|>1,6). There are two approaches for forming these small particles. Upset forging is used to forge small discs (height<100nm) and to shape the nanoparticle in specific areas. Press forging into nano-dies is used to forge more complex structures. In this way free-standing, high-strength, metallic nanoobjects may be shaped into components with dimensions in the 100 nm range. By assembling such nano-components, high-performance microsystems can be fabricated, which are truly in the micrometre scale (the size ratio of a system to its component is typically 10:1).

The development of suitable hot-forming processes, e.g. forging, is an important step towards the serial production of TiAl parts. Several microstructure parameters change during hot-forming. However, the underlying mechanisms can normally only be inferred from post process metallographic studies.

We used a deformation dilatometer modified for working in the HZG synchrotron beamlines at DESY for hot-deformation experiments. This setup enables the in situ monitoring of the interaction and evolution of microstructure parameters during processing. We observed the evolution of phase fractions, grain size and crystallographic texture during deformation while simultaneously recording the process parameters, like temperature, force and length change.

Here we present the hot compressive deformation behaviour of a Ti-43Al-4Nb-1Mo-0.1B (in at.%) alloy. Several specimens were deformed at three temperatures each with two compression rates. During the experiments the Debye-Scherrer diffraction rings were continuously recorded.

Balanced mechanical properties are needed for TiAl low pressure turbine blades envisaged for use in new generation aircraft engines. However, thermomechanical processing of γ-TiAl based alloys is a challenging task due to a small “processing window”. Isothermal forging, as state of the art process for this class of material, results in high productions costs and lower productivity. Due to these facts Bohler Schmiedetechnik GmbH & Co KG has developed a higher efficient “near conventional” thermomechanical processing technology. Lower die temperature and processing at standard atmosphere as well as the use of standard hydraulic presses with higher ram speed result in a highly economical process. Subsequent heat treatment strategies can be used to tailor microstructure and, therefore, mechanical properties according to customer needs. The paper summarizes our effort to establish a near conventional forging route for the fabrication of TiAl components for aerospace industry.

The scientific investigation involves the examination of copper alloy nails dated back tothe Roman Age. The artifacts were retrieved from a shipwreck discovered offshore Elbaisland (Italy). Further carbon dating measurements indicated the origin between 140 and300 AD. This work includes a brief overview of the ship’s routes and fortunes in order togive some context to the metallographic investigations. The experimental procedureinvolves the use of both Optical and Scanning Electron Microscopy (OM and SEM) coupledwith EDS and EBSD probes. The attention has been focused on the metallurgical features ofthe nails with the intent of casting some light on the metalwork processes of the RomanAge. The scientific trials revealed a “brazed” joint, which allowed to learn more aboutthe applications of this technique during this historical period. In addition, thetextural analysis yielded a strong work-hardening, evidence of an intense cold shapingprocedure in use by the Roman blacksmiths.

Manufacturing of high dimension steel rings impose several technological challenges. The lack of understanding of the principles and practices of quenching can result in inadequate hardness, excessive distortion or scrapping of costly machined components. This paper presents the results of an analytical study of the parameters of the quenching operation, among them the fluid dynamics of the agitation in the quenching media. Velocity components of the fluid were measured using an anemometer inside the quenching tank. Uniformity of agitation is compared with a Computational Fluid Dynamics (CFD) simulation. The CFD results revealed the impact of quench tank design, configuration and operation of impellers.

The properties of widely used Ni–Ti-based shape memory alloys (SMAs) are highly sensitive to the underlying microstructure. Hence, controlling the evolution of microstructure during high-temperature deformation becomes important. In this article, the “processing maps” approach is utilized to identify the combination of temperature and strain rate for thermomechanical processing of a Ni42Ti50Cu8 SMA. Uniaxial compression experiments were conducted in the temperature range of 800–1050 °C and at strain rate range of 10−3 and 102 s−1. Two-dimensional power dissipation efficiency and instability maps have been generated and various deformation mechanisms, which operate in different temperature and strain rate regimes, were identified with the aid of the maps and complementary microstructural analysis of the deformed specimens. Results show that the safe window for industrial processing of this alloy is in the range of 800–850 °C and at 0.1 s−1, which leads to grain refinement and strain-free grains. Regions of the instability were identified, which result in strained microstructure, which in turn can affect the performance of the SMA.

As 3D scanners and numerical simulation are now mature, we have made a benchmark by comparing simulation results with real forged parts. We did consider the complete forging process of a cylindrical part using hammer from the billet to the final part. This process has been simulated using a thermo-elasto-viscoplastic constitutive equation including the ductile damage with the implemented with the help of VUMAT subroutine provided by ABAQUS software. Before and after each step, the forged part is scanned and compared with the result of the FEM simulation in order to tune some of the process numerical simulation parameters.

In the present study the α2 and the γ texture in a Ti-45Al (at.%) alloy were analyzed by means of x-ray diffraction after hot deformation. The initial Ti-45Al powder compact exhibits a random texture and shows a relatively high amount of α2 phase (about 34 vol.%). Various hot compression tests were performed at temperatures ranging from 700 °C to 1100 °C with strain rates of 5·10–4 s–1 and 5·10–2 s–1 up to a true deformation of ε = –1.

Depending on the deformation temperature the γ-TiAl deformation texture consists of pure deformation components (700 °C) or components completely related to dynamic recrystallization (1100 °C). In contrast to the γ phase the α2 phase shows no remarkable changing of the deformation texture with increasing temperature. The α2 deformation texture basically consists of a similar component as it is known from hexagonal α-Ti, namely a tilted basal fiber. However, a significant influence of the deformation rate on the α2 texture formation is observed at temperatures above 800 °C. With increasing deformation temperature the α2 texture strengthens by applying a high deformation rate, whereas it weakens for a low deformation rate. This contrary behavior is attributed to the interaction of the α2 and γ phases during texture formation.

Les pièces de forge sont universellement reconnues pour leurs bonnes propriétésmécaniques, notamment en fatigue. L’approche proposée ici consiste à intégrer lasimulation du forgeage dans le dimensionnement en fatigue des pièces forgées. Le fibrageet le taux de corroyage sont deux caractéristiques principales du forgeage. À l’aide dulogiciel FORGE®, le fibrage est calculé tout au long desopérations de mise en forme. Ce fibrage, ainsi que les contraintes résiduelles, sontensuite introduits dans des outils de dimensionnement pour améliorer la prédiction ducalcul de durée de vie en fatigue. Les critères de fatigue actuels, basés sur des modèlesisotropes, ne permettent pas de valoriser le sens long de ce fibrage, et par là les piècesde forge, car c’est en général dans ce sens que ces pièces sont le plus sollicitées. Uneextension anisotrope du modèle de Papadopoulos est proposée sur la base d’une campagneexpérimentale effectuée sur des éprouvettes prélevées à 0°, 45° et90° par rapport à la direction de fibrage. Une modélisation à l’échelle micro(DIGIMICRO) permet également de mieux comprendre le rôle des inclusions sur lessollicitations en fatigue. La mise en place d’une chaîne de simulation virtuelle globale àl’échelle d’un composant industriel, associée à des modélisations microstructurales,permet de mieux comprendre et de quantifier le rôle du fibrage sur les propriétés enfatigue à grand nombre de cycles des pièces forgées.

Since their appearance during in the 1940 decade, nickel-base alloys are appreciated for their superior mechanical properties and microstructural stability at elevated temperatures and high stresses. They are typically used in jet-engines and land-based turbines for energy generation. Such materials, known as superalloys are in constant evolution as designers are encouraged to propose more efficient and powerful systems of propulsion and energy generation. This evolution leads to conceive and manufacture new superalloys capable to fulfill higher requirements. Alloy 718Plus® is emerging as an alternative material for the design and construction of components to be used in jet-engines and land-based turbines for energy generation. 718Plus® is a precipitation hardened nickel-base alloy designed to have the stability of superalloys similar to Waspaloy and the good processing characteristics of other materials as the 718 alloy. Since the early 2000 decade, ATI Allvac has lead a complete program in order to validate capabilities and properties of the 718Plus® alloy. Objectives for this effort include a characterization and its introduction as a viable material for the design and manufacture of components to be installed technologically. As part of this project, contoured rings made of 718Plus® are rolled considering industrial conditions. Several heat treatments, involving solution and precipitation processes are performed on segments extracted from involved contoured rings. Effects of such hot-working conditions and heat treatment procedures on properties as forgeability, tensile, hardness and stress-rupture characteristics are evaluated. Optical and electron microscopy are performed to evaluate microstructural properties as grain size and promotion of precipitates, in order to complement reported results.

Rings produced considering industrial conditions were manufactured by ring rolling procedures. In order to evaluate the effect of heat treating on AISI 405 (UNS S40500) structure and properties, statistical software Minitab® was considered for a design of experiments involving parameters as annealing temperature and soaking time. Samples/coupons from rolled rings were annealed according design of experiments. Tensile and hardness testing was performed and reported as response surface curves after statistical analyses. Alloy characterization includes observations performed by scanning electron microscopy for evaluation of phases in order to determine alloy behavior when exposed to annealing conditions.

The forging capabilities of two high-strength Fe3Al-based alloys have been evaluated. Based on these results one alloy has been used for forging steam turbine blades. Blades of about 600 mm length were successfully forged by a standard procedure otherwise employed for forging of 9-12 wt.% Cr steels. The forged steam turbine blades showed very good form filling, no pores and smooth surfaces. The blades were finished by cutting and grinding by standard procedures. The microstructure consists out of a Fe3Al matrix with additional Laves phase which predominantly precipitated on grain boundaries. The large Fe3Al grains in the cast precursors did only partially recrystallise during forging. This may be partially due to pinning of the grain boundaries by Laves phase precipitates. Cracks may form at those grain boundaries which are decorated with these brittle precipitates.

Replication of metallic high-aspect-ratio microscale structures (HARMS) by compression molding has been demonstrated recently. Molding replication of metallic HARMS can potentially lead to low-cost fabrication of a wide variety of metal-based microdevices. Understanding the mechanics of metal micromolding is critical for assessing the capabilities and limitations of this replication technique. This paper presents results of instrumented micromolding of Al. Measured molding response was rationalized with companion high-temperature tensile testing of Al using a simple mechanics model of the micromolding process. The present results suggest that resisting pressure on the mold insert during micromolding is governed primarily by the yield stress of the molded metal at the molding temperature and a frictional traction on the sides of the insert. The influence of strain rate is also considered.