Showing papers in "Acta Materialia in 2020"

TL;DR: In this article, the authors provide a detailed review of the deformation mechanisms of HEAs with the complex concentrated alloys (CCAs) with the FCC and BCC structures, highlighting both successes and limitations.

TL;DR: In this paper, a series of high-strength Al alloys for selective laser melting (SLM) additive manufacturing were designed and additively manufactured using atomized alloy powders.

TL;DR: In this article, the origin of dislocation structures in AM stainless steels was systematically investigated by controlling the effect of thermal stress through geometric constraints for the first time, and the results illustrate that dendritic micro-segregation, precipitates, or local misorientations influence how the dislocations organize during processing, but are not responsible for producing the organized cell structures.

TL;DR: In this article, a low-alloy Mg-Ca-based alloy that overcomes this strength-ductility trade-off is designed, which has an excellent tensile yield strength (∼425 MPa).

TL;DR: In this paper, a parameter-free theory for edge motion in BCC alloys qualitatively and quantitatively captures the strength versus temperature for both body centered cubic (BCC) high entropy alloys and other BCC HEAs and paves the way for theory-guided design of new high performance HEAs.

TL;DR: In this paper, a genetic algorithm was used to select the ML model and materials descriptors from a huge number of alternatives and demonstrated its efficiency on two phase formation problems in high entropy alloys (HEAs).

TL;DR: In this article, the in-situ formation of Al3Ti nanoparticles with a L12 ordered structure, which formed a coherent interface with Al matrix and therefore significantly promoted the heterogeneous nucleation of the α-Al during solidification of melt pools in the SLM process.

TL;DR: In this article, the authors investigated Si poisoning in Al-Si/Al-5Ti-B system by combining state-of-the-art electron microscopy, first-principles calculations and thermodynamic calculations.

TL;DR: In this paper, the role of lattice distortion and chemical short-range order (CSRO) in the nucleation and evolution of dislocations and nanotwins with straining in single crystal and nanocrystalline CoCrNi, a medium entropy alloy, was investigated.

TL;DR: In this article, a new series of B-site ordered double perovskites (RE2ZnMnO6) were successfully fabricated, and their structural and magnetic properties together with the cryogenic magnetocaloric performances were studied in detail.

TL;DR: In this article, the authors applied ab initio calculations to systemically characterize the chemical environment and magnetic moment effects of point defect formation in three equimolar alloys, namely: CoCrNi, CoCr NiFe, and CrCrNiFeMn, based on the investigation of a large number of statistical atomic sites.

TL;DR: In this paper, the authors investigate columnar to equiaxed microstructure transition during single-track laser powder bed fusion processing of 316L stainless steel using Gaussian (circular) and elliptical (transverse and longitudinal) laser beam shapes.

TL;DR: It is found that both solutions based on regression trees and NNs can provide accurate results for the specific problem, but NN- based solutions outperform regression-tree-based solutions in terms of their simplicity.

TL;DR: In this article, a parameter-free theory applicable to both fcc and bcc HEAs was proposed, with predictions of strength across a range of Fcc and Bcc alloys in quantitative and qualitative agreement with experiments.

TL;DR: In this paper, a theory of screw dislocations in random body-centered-cubic (BCC) alloys is developed and validated, which provides a framework for tailored design of new high-performance BCC alloys.

TL;DR: In this paper, a study was conducted on the microstructures and mechanical properties of nickel samples with two distinct types of heterostructures, including coarse-grained lamellae embedded in a matrix consisting of a very high density of dislocation structures.

TL;DR: In this article, the role of short-range order on the critical yield stress is quantified and compared with current solid solution models, where an energy topology approach is used to assess the local strengthening behavior in random solid solutions and annealed systems.

TL;DR: In this article, the effects of selective laser melting (SLM) parameters on the microstructure and mechanical properties of a recently discovered low alloy martensitic steel, AF9628, has been shown to exhibit strengths greater than 1.5 GPa with more than 10% tensile ductility, due to the formation of e-carbide phase.

TL;DR: In this paper, the eutectic formation in the multi-principal element systems is uncovered via data mining with machine learning (ML), where the critical elements and strongly associated elements were discovered.

TL;DR: In this article, the permittivity transition along with insulator-conductor conversion in BaTiO3/Ni composite is investigated along with the relationship between the negative permittivities and the reactance characters.

TL;DR: In this paper, the influence of heterostructural parameters on the evolution of hetero-deformation induced (HDI) stress and mechanical behavior during tensile deformation is not well understood.

TL;DR: In this article, the deformation twinning and basal slip governed plastic deformation in the conventional coarse-grained region, but twinning was suppressed when the grain size was refined down to several micro-meters.

TL;DR: In this article, the effect of high thermal gradients and cooling rates on equiaxed grain nucleation and growth in conditions similar to those experienced during additive manufacturing (AM) processes was analyzed.

TL;DR: In this paper, a method to eliminate hot cracking phenomena for aluminium alloys in Laser Beam Melting (LBM) is presented, focused here on the 6061 alloy, which is a precipitation-hardened aluminium alloy, containing magnesium and silicon as its major alloying elements.

TL;DR: In this article, a rotary swaging-based nano-grain alloys with an average grain size of 80nm and a dimension of ∅3mm-×-1000mm were presented, achieving a yield strength of 650MPa and ultimate tensile strength of 710MPa.

TL;DR: In this article, a multiscale dislocation-based model was built to describe, for the first time, the microstructural evolution and strain-hardening of TWIP (twinning-induced plasticity) Ti alloys.

TL;DR: In this article, the authors explore a different GBE processing route that leverages TB multiplication during recrystallization of austenitic 316L stainless steel produced via selective laser melting (SLM).

TL;DR: In this article, a high-entropy carbide ceramics (HECC) with a single-phase rock-salt structure was synthesized by spark plasma sintering, which was irradiated by 3-MeV Zr ions to 20 dpa at 25, 300, and 500°C.

TL;DR: In this paper, the phase stability and coarsening kinetics of L12-type coherent precipitates in a Ni-30Co-13Fe-15Cr-6Al-6Ti-0.1B (at.

TL;DR: In this paper, a multiphase flow model by bi-directionally coupling the discrete element method and finite volume method was developed to understand the physical mechanisms of the spattering and denudation phenomena in the laser powder bed fusion process.