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Amorphous PdSiAu-based metallic glass thin films (MGTFs) obtained by physical vapor deposition were deposited on multilayered graphene (MLGR) supported on Si/SiO2, where the MLGR is carried to the top by upward pressure of the deposited atomic layer passing through the crystal lattice of graphene. Samples were electrochemically hydrogenated by chronoamperometry and characterized by cyclic voltammetry in 0.1 M H2SO4. MLGR-containing samples have a prominent Raman peak at 1415 cm−1. This sample shows ∼2.6 times larger hydrogen desorption charge and ∼4.5 times larger electrocatalytic hydrogen activity compared to the MLGR-free counterparts. Furthermore, the capacitance retrieved from the simulation of electrochemical impedance data indicates a ∼2.6 times increase upon MLGR inclusion. High-resolution (scanning) transmission electron microscopy after hydrogenation corroborates the existence of nm-sized PdHx crystals around the MGTF–Si/SiO2 interface and the presence of a graphene layer on top of the MGTF due to bond breaking between the MLGR and Si/SiO2. The enhanced hydrogen activity due to the synergistic effect of MLGR and MGTF layer-by-layer nanostructure reveals itself in the diffusion kinetics, where 50% faster hydrogen ion transfer into the MGTF is obtained when the MLGR top layer is present. The areal and volumetric hydrogen desorption charge exceed almost all the considered Pd-based counterparts, especially when comparing systems with similar thicknesses. Hence, the developed hybrid nanostructure can be envisaged as an alternative ultra-high hydrogen charger for small-scale applications. [ABSTRACT FROM AUTHOR]

The selective laser melting process, commonly known as laser‐based powder bed fusion (LB‐PBF), enables the production of structures with unprecedented degrees of freedom that represents an excellent condition for development of metallic implants for biomedical applications. Herein, the effects of laser energy density on relative density and microstructure (presence of internal defects) of cp‐TiGd2 fabricated by LB‐PBF are studied. Additionally, the influence of printing orientation and different surface treatments on surface topography and biocompatibility are investigated. The aim of the research is to develop additive manufacturing process parameters that can achieve full density of cp‐TiGd2 with satisfactory biocompatibility, as a low‐cost alternative to biomedical materials such as Ti–6Al–4 V and Ti–6Al–7Nb. A wide range variation of process parameters leads to an optimized process with high density up to 99.97 ± 0.008%, improved surface roughness, and noncytotoxicity in horizontal and inclined as‐built condition, as well as in Al2O3 (blasting angle 0°) condition. [ABSTRACT FROM AUTHOR]

In situ alloying and fabricating glassy structures through a layer‐by‐layer fashion approach are challenging but have high potential to develop novel‐graded materials. For the first time, this cost‐effective approach is applied to additive manufacturing (AM) of a Zr‐based bulk metallic glass (BMG) from high‐entropy alloys (HEAs). A newly developed composition of Zr40Al20Cu20Ti20 is fabricated through laser powder bed fusion (LPBF). Process parameters are optimized within a wide range of laser power (50–200 W) as well as scanning speed (50–800 mm s−1). In all printed samples, microscopic and compositional examinations reveal no glass formation, but very fine grains and CuTi and AlTi nanocrystals. Some glassy transitions at the interfaces may be encouraged to occur with proper melting and mixing. However, the main reason for not obtaining a glassy matrix is the substantial proportion of unmelted Zr raw powder throughout the structure as spherical particles. Consequently, glass formation can be hindered by a considerable amount of compositional deviation. During LPBF, in situ alloying poses significant challenges to developing BMGs. Hence, the various stages of the process, including raw material specifications, laser settings, and process parameters, should be investigated further. [ABSTRACT FROM AUTHOR]

The correlations between process conditions, microstructure, and mechanical properties of additively manufactured components are not fully understood yet. In this contribution, three different hatch strategies are used to fabricate rod‐like samples from S316L stainless steel, which are further investigated using synchrotron diffraction, optical microscopy, and tensile tests. The results indicate the presence of ⟨110⟩ biaxial and fiber textures, whose sharpness depends on the applied hatch strategy. Mechanical tests reveal a strong correlation of the samples' response to the observed anisotropy in the plane perpendicular to the build direction. Even though the average yield and ultimate tensile strengths of around 475 and 500 MPa, respectively, do not differ significantly, the stress–strain behavior can be correlated with the observed in‐plane anisotropy. Particularly, twinning‐induced plasticity, a distinct increase of the work hardening rate at larger strains and elliptical necking are observed in some samples with biaxial (Goss) texture. These findings indicate that texture design by means of applying dedicated hatch strategies can be used to effectively tune the multiaxial deformation behavior of components produced by laser powder bed fusion. [ABSTRACT FROM AUTHOR]

CoCrFeMnNi high‐entropy alloy (HEA)/AISI 316L stainless steel bimetals were additively fabricated using selective laser melting (SLM). The bimetal structure comprises three regions, i.e., CoCrFeMnNi‐HEA, AISI 316L stainless steel, and an interface between CoCrFeMnNi‐HEA, AISI 316L stainless steel. SLM processing results in the formation of columnar grains extending over many built layers epitaxially in a preferential <100> growth direction. The Vickers microhardness ranges mainly between 250 and 275 HV0.5 in all three observed regions. In addition, only a marginal variation in tensile strength is observed between the CoCrFeMnNi‐HEA, AISI 316L stainless steel, and the CoCrFeMnNi‐HEA/AISI 316L stainless steel bimetal. The unique higher work hardening behavior of the CoCrFeMnNi‐HEA prevents failure along the CoCrFeMnNi‐HEA side in the bimetallic structure during plastic deformation. The CoCrFeMnNi‐HEA shows higher pitting susceptibility than the AISI 316L stainless steel in the bimetallic structure due to its lower pitting potential. Further, the presence of pores and lack of fusion spots further decreases the pitting resistance of the CoCrFeMnNi‐HEA. Hence, the bimetal is prone to more preferential corrosion attack along the CoCrFeMnNi‐HEA side due to its anodic behavior and defects. [ABSTRACT FROM AUTHOR]

We present variation of the magnetic properties of Fe77.8Nb0.2B14P6C2 amorphous alloys vitrified at different temperatures by changing the atomic structures dependent on the critical cooling rate. The thermophysical properties of the amorphous state achieved after quenching the melt with cold nitrogen atomization gas are compared with those obtained using hot nitrogen gas with a temperature corresponding to the supercooled liquid of the alloy above the glass transition (Tg) but below crystallization temperature (Tx). The differently vitrified Fe77.8Nb0.2B14P6C2 glasses represent different states of high pressure gas atomized amorphous powder at different temperatures obtained by adjusting the gas temperature during the atomization process. The magnetic properties of these different amorphous powders are also investigated. The saturation magnetic flux density of slowly cooled Glass2 is 1.38 T with 450 A/m coercivity corresponding to "semi-soft" magnetic materials. The fast cooled Glass1 powder shows typical soft magnetic properties with lower coercivity (174 A/m), even though the saturation magnetization flux densities are similar in both identical compositions of amorphous powder due to its entropy difference related to the formation of clusters. We can control the magnetic property of amorphous materials from soft to half-soft by adjusting freezing temperature and ordering of atoms. [ABSTRACT FROM AUTHOR]