Showing papers in "Acta Materialia in 2021"

TL;DR: In this paper, the authors conduct several dedicated transmission electron microscopy (TEM) studies to investigate these strengthening mechanisms and identify that cell walls follow specific crystallographic orientations, forming wider stacking faults while oxide precipitates are confined inside cell walls.

TL;DR: In this paper, a new grade of γ/γ′ nickel-based superalloy for the additive manufacturing process is designed using computational approaches, taking account of the need to avoid defect formation via solidification and solid-state cracking.

TL;DR: In this article, the SBT doping into BNBLT ceramics could effectively decrease grain size, resulting in enhancement breakdown strength, achieving a superior balance between recoverable energy density (Wrec ~ 4.55 J/cm3) and efficiency (η > 90%).

TL;DR: In this paper, a unique texture formation in Inconel 718 (IN718) using a bidirectional laser scan in a laser powder bed fusion (LPBF) process for tailoring the mechanical properties was demonstrated.

TL;DR: In this paper, the authors report that refinement of magnesium grains can not only improve its strength, but also its ductility, due to the activation of more slip systems, and they find that fine-grained Mg exhibits enhanced work hardening and ductility as well as uniform elongation.

TL;DR: In this article, a comprehensive review of the current understanding of the structure-property correlations in AM alloys is provided, with an emphasis on the interplay between the microstructures and process attributes in determining the structural integrity of AM components in terms of properties such as near-threshold fatigue crack growth rate, fracture toughness, and fatigue strength.

TL;DR: In this paper, an equiatomic CrFeNi medium-entropy alloy (MEA) that constitutes a cornerstone of austenitic stainless steels and Fe-based superalloys is investigated.

TL;DR: In this article, a grain boundary segregation engineering method was proposed to counteract the hot-cracking problem in additive manufacturing of metals and alloys, using available thermodynamic and kinetic database information.

TL;DR: In this article, the authors present data-driven discussions with examples that have been collected from the fields of geology and materials science over the past 50 years to highlight critical thermodynamic parameters and principles that can be used for the design of HEOs.

TL;DR: In this article, a parametric experimental study on the role played by the power (P), velocity (VL) and profile (top-hat or Gaussian) of the laser on the porosity, inclusion content and microstructural evolution of in-situ alloyed laser powder bed fusion (LPBF) manufactured Ti34Nb was conducted.

TL;DR: The current status of the interatomic potential field, comparing the strengths and weaknesses of the traditional and ML potentials, is reviewed in this paper, where a new class of potentials is introduced, in which an ML model is coupled with a physics-based potential to improve the transferability to unknown atomic environments.

TL;DR: In this paper, a detailed understanding of how the processing conditions control the micro- and mesostructures and, in turn, the mechanical performance, especially regarding fracture resistance, is presented.

TL;DR: In this article, the authors examined the cracking susceptibility of six binary Al-Si alloys, whose compositions were strategically chosen at hypo-, near-, and hyper-eutectic compositions, were gas atomized into alloy powders, and processed by LPBF.

TL;DR: In this paper, the authors studied the early stages of the radiation damage response of high entropy alloys (HEA) using molecular dynamics simulations of collision cascades induced by primary knock-on atoms (PKA).

TL;DR: In this article, the authors reported a stable tensile recovery strain induced by a Ni4Ti3 nanoprecipitate in a Ni50.4Ti49.6 shape memory alloy (SMA) fabricated via selective laser melting (SLM), followed by a discussion on the underlying physical mechanism.

TL;DR: In this paper, the laser powder bed fusion (L-PBF) was used to fabricate fully dense, near-equiatomic (Ni50.1Ti49.9) and Ni-rich NiTi (Ni4Ti3 precipitates.

TL;DR: In this paper, equal channel angular pressing (ECAP) was employed to improve the yield strength of the most well-known HEA, CoCrFeMnNi, through microstructural refinement.

TL;DR: In this article, the authors demonstrate a relationship derived in terms of the electronegative difference of elements to characterize solid solution strengthening (SSS) for single-phase high entropy alloys.

TL;DR: In this paper, a Monte Carlo method is applied to develop a model for numerical simulation of dynamic recrystallization in friction stir welding of aluminum plates, and the correlation of the Monte Carlo simulation step and the real time is calibrated.

TL;DR: In this paper, the authors developed a novel (NiCoCr)92Al6Ta2 medium-entropy alloy (MEA) towards superior cryogenic mechanical properties via elaborating the chemical composition designing and the thermo-mechanical processing.

TL;DR: In this paper, an integrated computational materials engineering case study with the aim of improving the strength and ductility of Titanium (Ti) alloys is presented, where the electronic properties of elemental building blocks were derived from high-throughput first-principles calculations and presented in the form of the Mendeleev periodic table, including their electron work function, Fermi energy, bonding charge density, and lattice distortion energy.

TL;DR: In this paper, a multi-layered Zr-based BMGC with a well-controlled gradient in volume fraction of the crystalline dendrites via laser additive manufacturing (LAM) was designed to allow site-specific control of the cooling rate and the resultant microstructure.

TL;DR: In this article, the microstructure, nanoparticle evolution, and mechanical properties of ODS steels prepared by dielectrophoretic controlled adsorption of 0.08 wt% laser-synthesized yttrium oxide (Y2O3) on an iron-chromium ferritic steel powder (PM2000) were evaluated by electron backscatter diffraction, scanning electron microscopy-energy-dispersive X-ray spectroscopy, and atom probe tomography.

TL;DR: In this article, a short duration/low temperature single-step pre-ageing process on a Cu-lean grade of AA6016 was investigated using a combination of atom probe tomography and first principles density functional theory simulations, revealing and explaining the atomic-scale microstructure arising from this thermomechanical process.

TL;DR: In this article, an extraordinarily high yield strength, far beyond the predicted values from the Hall-Petch relation and the ROM, is achieved in a specially designed layered titanium that is characterized by alternating coarse-and fine-grain layers (C/F-Ti) where the grain sizes match the layer thicknesses in both the coarse and fine-grained layers.

TL;DR: In this article, the deformation behavior of single crystals of the equiatomic Cr−Mn−Fe−Co−Ni high-entropy alloy (HEA) with the face-centered cubic structure has been investigated in tension and compression as a function of crystal orientation and temperature from 10 k to 13 k.

TL;DR: In this paper, a quasi-in-situ method was carried out to observe the growth behavior of intermetallic compounds (IMCs) in Cu/Sn-3.0Ag-0.5Cu/Cu micro solder joints with single β-Sn grain during aging with and without temperature gradient (TG).

TL;DR: In this article, a thermomechanical processing concept which is capable of exploiting the full industrial application potential of recently introduced AlMgZn(Cu) alloys is presented. But the authors do not consider the impact of pre-strain on the hardening response and the role of Cu additions in early-stage cluster nucleation.

TL;DR: In this article, the authors used transmission electron microscopy (TEM) at different tensile strains of interstitial-free steel with ultrafine-grained (UFG) size to clarify the underlying mechanisms of the extra-hardening behavior from the Hall-Petch plot and the discontinuous yielding behavior from axial tensile tests.

TL;DR: Wang et al. as mentioned in this paper proposed a machine learning strategy to design alloys with remarkable properties by screening key alloy factors through correlation screening, recursive elimination and exhaustive screening, and then designing composition iteratively through Bayesian optimization.