This study presents a comprehensive scale-bridging characterization approach to investigate acicular ferrite nucleation in electron beam welded S355 ML steel, demonstrating the critical role of titanium oxide particles in promoting fracture-resistant microstructures for offshore wind monopile applications. Using a multi-technique methodology spanning light microscopy, scanning electron microscopy (SEM), electron backscatter diffraction (EBSD), energy dispersive X-ray spectroscopy (EDS), transmission electron microscopy (TEM), and transmission Kikuchi diffraction (TKD), the researchers identified and analyzed particles that serve as nucleation sites for acicular ferrite formation. This entry won the prestigious 2024 Jacquet-Lucas Award for Excellence in Metallography at the International Metallographic Contest held during IMAT in Cleveland, October 2024.

Single crystal and directionally solidified casting processes are among the most complex techniques available, requiring stringent process control and a thorough understanding of engineered materials and specialty alloys. This article examines how an aerospace material company utilizes advanced investment casting techniques to create components that meet the increasingly demanding requirements of modern aerospace and gas turbine engines. The article highlights how solidification modeling and integrated computational materials engineering (ICME) have accelerated development processes by predicting material behaviors and optimizing casting parameters without extensive experimental testing.

A dilatometry test is an effective method for characterizing the phase transformation kinetics for heat treatment processing of steels. This study uses computer modeling to examine the root causes of inaccuracies in measured dilatometry displacement data using a quench dilatometer.

Martempering involves cooling steel from the austenitizing temperature and rapidly cooling into either specially formulated petroleum oil or a molten salt bath with a specific composition to a temperature slightly above the martensite start (Ms) transformation temperature of the steel. Martempering is performed to reduce distortion problems that may be encountered with conventional quenching methods. This article, adapted from the latest ASM Handbook on quenching and quenchants, describes suitable steels for martempering and variables that influence the process.

Both shape memory and elastocaloric effects are related to the reversible martensitic phase transformation. For the shape memory effect, thermal energy is used to drive the material through the phase transformation and recover its original shape. For the elastocaloric effect, mechanical energy is used to induce phase transformation, and the associated latent heat is used to pump heat for cooling or heating. Heat pumps based on the elastocaloric effect have a low environmental impact and are highly efficient. However, designing a prototype to harvest the full potential of the elastocaloric effect has been challenging. This article summarizes prototyping efforts undertaken by three different research groups.

John J. Croat and Masato Sagawa simultaneously and independently invented the world’s most powerful permanent magnet, the neodymium (NdFeB) magnet, and established two different manufacturing methods to produce it. Their achievement is recognized by the 2023 Honda Prize, awarded by the Honda Foundation. This article highlights each inventor’s research contributions.

Annealing and normalizing both involve heating metal to a temperature and cooling back to room temperature and are differentiated by the metals involved and rate of cooling. This article is an overview of annealing and normalizing processes.

Ni-ion irradiated NiTi is nearly 50% harder, retains 85% recoverable deformation, and has reduced hysteresis. This work explores the feasibility of using ion beam modification to modulate the austenite to martensite phase transformation in NiTi, thereby achieving novel or localized properties in near-surface regions.

The second article in this series looks at materials testing, microstructural evaluation, mechanical testing, and residual stress and distortion using the DANTE Controlled Gas Quenching process.

A new method to control distortion in difficult-to-quench geometries addresses the nonuniform cooling inherent in most gas quenching processes. This article describes the development of a controlled gas quenching prototype unit design and its operation. The prototype unit constructed was able to achieve great control within the temperature range of 400 to 100°C, using varying rates of temperature change.

Novel methods for altering the mechanical properties of functionally graded orthodontic medical devices leads to new applications. This article highlights recent applications of selective vaporization to enable functional grading of shape memory alloys in medical devices for the dental industry.

Creep strain behavior during cooling was investigated by physical simulation, giving insight into the relationship of flow stress behavior and microstructure as a function of temperature and cooling rate.

New research explores a zirconia-based shape memory ceramic that exhibits a unique type of electrically triggered martensitic transformation.

Through a series of case studies, the benefits of micro x-ray fluorescence (XRF) over traditional XRF are demonstrated in the power generation industry for informing weld procedures, identifying root cause, and providing materials or component specifications.

Induction hardening parts with small grain size achieves higher fracture strengths, but close control of thermal cycles is required to prevent grain growth.

Deformation-induced martensite phase transformation during room temperature forming of austenitic stainless steel leads to higher residual stress. This article discusses the results of a study to determine the relationship between deformation-induced martensite phase transformation and residual stress in AISI Type 304 austenitic stainless steel (nominal 18% Cr, 8% Ni) after stamping.

New methods for processing titanium alloys offer the potential to enhance mechanical properties while reducing component cost. This article discusses innovative and potentially lower cost fabrication processes including additive manufacturing (AM), superplastic forming/diffusion, hot isostatic pressing (HIP) near-net shapes from prealloyed powder, injection molding, rapid solidification, mechanical alloying, and thermohydrogen processing.

Using virtual tools to study aluminum cylinder head quenching processes delivers valuable information for process design and optimization. In this study, cooling curves and temperature gradients generated by air and water quench modeling methods were used to evaluate quenching performance for various quenching configurations.

A new process called nanofunctionalization was successfully used to control the solidifying microstructure during additive manufacturing and produce crack-free 7000 and 6000 series aluminum alloys for the first time.

Affordable bulk production of a newly developed nanostructured bainitic steel is possible without using severe deformation or complex heat treatments. This article discusses the characteristics and significance of nanostructured bainite in terms of the transformation mechanism.