Laser powder bed fusion (LPBF) faces challenges when fabricating intricate structures with thin elements, comparable to the laser beam size, and thus requires precise deposition of melt spots. We devised a method for creating a Fe-15Mn-0.8C filigree structure via LPBF with a pulsed Gaussian laser beam. Initially, single melt spots were deposited to determine the optimal exposure time depending on laser power and laser spot size. Arrays of single melt tracks were then deposited, varying laser spot size, power, and point distance between spots, with the depth and width of each melt pool quantified. Through correlation analyses, key parameters were identified: exposure time and laser power for uniform melt spots, and laser power and point distance for melt pool depth. Utilizing the normalized enthalpy criterion, optimal parameter values were determined. We successfully LPBFfabricated fully dense, 80 mu m diameter pillars representing the simplest filigree structures and finally a complex stent structure with 99.5 % relative density. This approach can be adapted to other materials and additive manufacturing technologies using pulsed laser beams, streamlining experimentation.

The past several decades witnessed a significant advance in the X-ray based analytical devices, which were employed in various applications ranging from airport security to material analysis. Particularly, since the early 1990s, much work has been devoted to employ various kinds of real time (in situ) X-ray based analytical tools such as in situ X-ray diffractometers (XRD), in situ X-ray absorption spectroscopy, and in situ X-ray tomography to understand the redox reactions within the lithium-ion batteries. Amongst components in the lithium-ion batteries, anode materials play an important role in that they are responsible for Li+ storage during the charging process. Reaction mechanisms of graphite, Si, and many other prospective anode materials have been elucidated by various in situ X-ray analytical tools but none of the comprehensive summary and evaluation on the current status of the research and future directions on employing in situ X-ray based analysis for further investigating these anode materials are presented up to this point. In this review, we have examined and highlighted our focus on X-ray based analysis that was used to probe the reaction pathway of various anode materials used for lithium-ion batteries, which provides a milestone and comprehensive understanding for reaction mechanism of anode materials in lithium-ion batteries using in situ X-ray methods.

Recently, Fe-Cr-Ni-Al-Ti ferritic alloys strengthened by L21-type Ni2TiAl precipitates have demonstrated superior high-temperature strength compared to conventional ferritic steels. However, it still shows a lower hightemperature strength than that of Ni-based superalloys. Therefore, in the current study, we designed new ferritic alloys to improve the high-temperature strength by introducing L21-Co2TiAl precipitates, known as having better high-temperature properties than the Ni2TiAl structure. Specifically, the Ni element has been replaced with the Co element. In addition, the Ti element has been adjusted because the structural evolutions of precipitates, such as composition, lattice misfit and size rely on the Ti content. For instance, the addition of 2 wt% Ti forms a semicoherent Co2TiAl precipitate with a relatively low density of misfit dislocations. More Ti addition up to 6 wt % leads to an increase in the lattice parameter of the precipitate, while that of the Fe matrix remains unchanged, which results in an increased lattice misfit. The increased lattice misfit causes a higher amount of misfit dislocations, which leads to a reduction of the elastic strain field around the precipitates. It was found that the semicoherent interface with a high level of the elastic strain field (2 wt % Ti), as compared to the precipitates with a high amount of misfit dislocations (4 and 6 wt % Ti), plays a crucial role in enhancing the mechanical properties at 973 K. In addition, the designed ferritic alloys show superior strength, compared to the previously-reported ferritic alloys.

Shear bands are nanoscale topologically complex planar shear defects mediating plasticity in metallic glasses and a complete understanding of the shear banding phenomenon requires their three-dimensional characterization; however, we have been unable to tomographically and not-destructively reconstruct the path of shear bands inside a sample until now as X-ray absorption (or phase contrast) tomography is currently unable to distinguish shear bands from the surrounding matrix. Here, we overcome this limitation using the strain field generated by shear bands in the adjacent material as a local probe for X-ray diffraction tomography. This strain field is the analogue of the contrast agents used in conventional clinical tomography, allowing us to non-destructively reconstruct the shear band paths within the glassy specimens. Tomography is based on collecting a series of projections recorded at different angles while the specimen is rotated about a single axis. In this work, we first use full-angle tomography (reconstruction based on projections collected over 360°), which allows reconstructing the paths in excellent detail revealing features of shear banding that are not accessible to other analytical tools. A dataset with missing angles (projections over less than 360°) degrades the reconstruction but opens the door to in-situ measurements during deformation.

Owing to the layer-by-layer processing, laser powder-bed fusion (LPBF) allows to overcome the size limitation imposed by the high cooling rates necessary for the synthesis of bulk metallic glasses (BMGs). The fabrication of amorphous and highly dense parts via LPBF is however very challenging, since the processing parameters affect both requirements in a contrasting manner. Here, a large number of specimens is fabricated from the glass-forming Zr52.5Cu17.9Ni14.6Al10Ti5 alloy by LPBF at varying processing conditions. Processing maps of amorphicity and density are provided and evaluated concerning porosity, structural relaxation and crystallization. Optimum processing conditions for maximized density and amorphicity are identified. The present dataset is designed to quantify the correlation between relative density, amorphicity, volumetric energy density and normalized enthalpy criteria. Pearson and Spearman correlation analyses show an equally strong dependence between both criteria and the relative density and an inverse moderate dependence with amorphicity. Based on the results, a modified enthalpy criterion is deduced. It correlates strongest with density amongst the non-dimensional parameters.

High-power laser power bed fusion (HP-LPBF) with a large flat-top laser beam allows additive manufacturing of components at much higher build-up rates than conventional LPBF, since thicker powder layers can be processed. This makes this technology attractive for industry due to the augmented productivity. Here, we have utilized HPLPBF to fabricate Al-33Cu (wt%) specimens at differing layer thickness and laser power. Based on the average spacing of the lamellae of the eutectic microstructure, the cooling rate inherent to HP-LPBF was experimentally determined as a function of the processing conditions. At the lowest layer thickness (50 & mu;m) and laser power (500 W), the cooling rate amounts to about 90000 K/s, whereas it drops to about 15000 K/s for HP-LPBF with the largest layer thickness (200 & mu;m) and highest laser power (1000 W). When the base plate is additionally preheated, the cooling rate prevailing during solidification decreased to about 5000 K/s. Our findings demonstrate that relatively low cooling rates are effective during HP-LPBF at high build-up rates being tantamount to high productivity. It should be considered that such drastic changes in cooling rate may strongly affect the microstructure formation, the properties and hence performance of the corresponding additively manufactured component.

The CoCrFeMnNi high entropy alloys (HEAs) performs large work strengthening with excellent deform ability. The work strengthening and deformation mechanism are facilitated by dislocation activities and dislocation accumulation. In this study, the dislocation density and microstructure of the CoCrFeMnNi HEA were characterized by the neutron line profile analysis using convolution multiple whole profile (CMWP) method and EBSD in a comparison with a binary FeNi alloy. The CoCrFeMnNi HEA and FeNi alloy were plastically deformed by rotary swaging until 85% area reduction. The characteristics (e.g., low stacking fault energy, local variation with different atom species) rising from the high compositional complexity of the CoCrFeMnNi HEA cause different dislocation activities and levels of dislocation accumulation from the binary FeNi alloy. The dislocation density of the CoCrFeMnNi HEA continuously increased during the cold swaging and was significantly larger than the FeNi alloy. The larger dislocation accumulation of the CoCrFeMnNi HEA is facilitated by higher compositional complexity, extensive dislocation arrangement, and strong grain fragmentation. The increasing heterogeneity of dislocation distribution in the CoCrFeMnNi HEA was contributed by dislocation cell formation and increasing geometrically necessary dislocations (GNDs). The larger work strengthening in CoCrFeMnNi HEA is correlated with large total dislocation density during cold swaging. (c) 2021 Elsevier B.V. All rights reserved.

This study investigated the effect of the secondary phases on multi-step phase transitions and the magnetocaloric properties depending on the Ge content in the MnFeCoPSiGe alloys. Two-step phase transitions were observed by the variations of the Fe2P-type hexagonal structure (first-order) and secondary phases (second-order). The Curie temperature alters with non-linear behavior consistent with change of the lattice parameters. In addition, the magnetic entropy change decreased with the increase of the Ge content and, subsequently, fractions of the secondary phases. However, the morphological variation of microstructure, distributed as a circular-type shape of the Fe2P-type hexagonal structure in the Ge-rich matrix, increased the magnetic entropy change. Therefore, the addition of Ge enables the control of the Curie temperature to be applicable for high temperature operating devices. The control of the secondary phases and morphology of the microstructure are crucial to improve the phase transition and magnetic entropy change.

The structure of matter at the nanoscale, in particular that of amorphous metallic alloys, is of vital importance for functionalization. With the availability of synchrotron radiation, it is now possible to visualize the internal features of metallic samples without physically destroying them. Methods based on computed tomography have recently been employed to explore the local features. Tomographic reconstruction, while it is relatively uncomplicated for crystalline materials, may generate undesired artifacts when applied to featureless amorphous or nanostructured metallic alloys. In this study we show that X-ray diffraction computed nanotomography can provide accurate details of the internal structure of a metallic glass. We demonstrate the power of the method by applying it to a hierarchically phase-separated amorphous sample with a small volume fraction of crystalline inclusions, focusing the X-ray beam to 500 nm and ensuring a sub-micrometer 2D resolution via the number of scans.

Single-phase solid-solution refractory high-entropy alloys (RHEAs) have been receiving significant attention due to their excellent mechanical properties and phase stability at elevated temperatures. Recently, many studies have been reported regarding the precipitation-enhanced alloy design strategy to further improve the mechanical properties of RHEAs at elevated temperatures. In this study, we attempted to develop precipitation-hardened light-weight RHEAs via addition of Ni or Co into Al0.8NbTiV HEA. The added elements were selected due to their smaller atomic radius and larger mixing enthalpy, which is known to stimulate the formation of precipitates. The addition of the Ni or Co leads to the formation of the sigma precipitates with homogeneous distribution. The formation and homogeneous distribution of sigma particles plays a critical role in improvement of yield strength. Furthermore, the Al0.8NbTiVM0.2 (M = Co, Ni) HEAs show excellent specific yield strength compared to single-phase AlNbTiV and NbTiVZr RHEA alloys and conventional Ni-based superalloy (Inconel 718) at elevated temperatures.

Refractory high-entropy alloys (RHEAs) show a great potential as structural materials due to their remarkable properties, such as high strength and thermal stability. Despite these advantages, the RHEAs still suffer from the limited ductility at room temperature. To overcome the strength-ductility trade-off, the new RHEA design strategy, transformation-induced plasticity (TRIP) HEAs, have been developed by applying metastability-engineering approach. With the newly developed RHEAs design strategy, we designed metastable RHEAs, TiZrHfVxNbxTax (x = 1.0, 0.5 and 0.1) with decrease of the beta-stabilizing elements (V, Nb, and Ta) to promote the transformation-induced ductility and work-hardening capability. The proper addition of the n-stabilizing elements (V, Nb, and Ta) into the ternary equi-molar TiZrHf alloy (TiZrHfV0.1Nb0.1Ta0.1) leads to stress/strain-induced phase transformation from the body-centered cubic (BCC) to hexagonal-close-packed (HCP) alpha' and/or orthorhombic alpha '' phases. Detailed studies on the phase transformation sequence during the deformation were carried out using X-ray diffraction (XRD), electron back-scattered diffraction (EBSD), and transmission-electron microscope (TEM), which revealed the stepwise phase transformation that is responsible for the strong strain hardening behavior. Furthermore, we further suggested the new transformation-induced-plasticity (TRIP) HEA design strategy, applying the Bo-Md approach. (C) 2021 Elsevier B.V. All rights reserved.

Co61Ta6B33, Co59Ta8B33, Co57Ta10B33 and Co53Ta10B37 bulk metallic glasses (BMGs) exhibit a good combination of the ultra-high fracture strength in the range of about 5.4-6.2 GPa, Vickers hardness of 1459-1653 HV0.2 and plastic strain of 0.3-3.2%, depending on composition. Glass forming-ability and physical properties of Co-Ta-B BMGs are discussed in relationship to the Ta and B content and atomic structure. Crystallization upon isochronal and isothermal annealing is studied using differential scanning calorimetry and X-ray diffraction. A novel crystalline phase with similar to Ta2Co15B8 or similar to TaCo7B4 formula is shown to form upon glass annealing. The incubation time for isothermal crystallization in the supercooled liquid state near T-g is supposed to be sufficient for thermoplastic forming of Co-Ta-B BMGs. (C) 2020 Elsevier B.V. All rights reserved.

Ferritic steels are attractive as a candidate material for high temperature applications due to high thermal conductivity, low thermal expansion coefficient, and low cost compared to austenitic steels or Ni-based superalloys. Recently, Fe-Cr-Ni-Al-Mo(-Ti) ferritic alloys reinforced by B2-NiAl and/or B2-NiAl/L2(1)-Ni2TiAl hierarchical precipitates has been reported to improve the microstructural stability and mechanical properties at elevated temperatures. In the present study, we attempted to further improve the mechanical properties of the Fe-Cr-Ni-Al-Mo(-Ti) alloys strengthened by B2/L2(1) hierarchically-structured precipitates via introducing fine Laves phases. Specifically, Zr, Hf and Ta elements, which is well known to form the Laves phases, were added into previously studied Fe-Cr-Ni-Al-Mo(-Ti) ferritic alloys. The present study reveals that the combination of Laves phases and B2/L2(1) precipitates is effective in enhancing the mechanical properties of Fe-Cr-Ni-Al-Mo(-Ti) ferritic alloys at room and 973 K. (C) 2020 Elsevier B.V. All rights reserved.

Coherent precipitates hardening is currently emerging strengthening mechanism of the various high entropy alloys (HEAs). Recently, CrMnFeCoNiAlx HEAs have been studied to show a phase transition from face-centered-cubic (FCC) to body-centered-cubic (BCC) and formation of coherent precipitates (B2-NiAl) within the BCC matrix. The coherent precipitates in the CrMnFeCoNiAlx alloys could contribute to increase the strength but lead to considerable reduction of the ductility. The present work systematically investigated a series of CrMnFeCoNiAl0.5Tix alloys to further improve the strength and plasticity, as compared to the previously reported CrMnFeCoNiAlx HEAs. As a result, an increase of Ti addition leads to the phase transition from FCC to BCC and formation of lamellar structure and hierarchical precipitates reinforced by B2-NiAl and L21-Ni2TiAl phases. Excellent mechanical properties were achieved from CrMnFeCoNiAl0.5Ti0.1 and CrMnFeCoNiAl0.5Ti0.2 alloys. The mechanical properties of the CrMnFeCoNiAl0.5Tix alloys were discussed via theoretical strengthening mechanisms.

Based on the hypothesis of lattice distortion, compositional complexity of high entropy alloys (HEAs) induces severe lattice distortion. Recent studies on the experimental and theoretical approaches to lattice distortion have been made to evaluate this hypothesis. However, the understanding of this effect is not complete due to their highly complex compositions and limited direct evidence. This work was designed to systematically study the effect of compositional complexity from unary to quinary compositions (Ni, FeNi, FeNiCo, FeNiCoCr and FeNiCoCrMn). To focus on the effect of interactions between constituent elements, the microstructural effect was minimized by controlling similar microstructural features such as grain size and residual strain. The micro lattice strain was evaluated on X-ray line profile analysis using the Williamson-Hall method and the local lattice strain was assessed by using pair distribution function (PDF) method through the total scattering data using the synchrotron X-ray diffraction measurement. Analysis on both the micro and local scales indicates that severe lattice distortion is not evident in FeNiCoCrMn HEA. Lattice strain and solid solution hardening are comparable between FeNiCoCrMn HEA and its sub-alloys. The high compositional complexity of FeNiCoCrMn HEA does not lead to a strong effect on lattice strain and solid solution hardening.

The biocompatible Ti 40 Cu 34 Pd 14 Zr 10 Sn 2 bulk metallic glass was rapidly heated,also known as flash-annealed,at varying heating rates up to 1579 K/s.Thereby,the phase formation was characterized via advanced in-situ highenergy X-ray diffraction.It has been found that the evolving kinetic constraints can be used as a tool to deliberately alter the crystalline phase formation.This novel processing route permits to select phases to crystallize to a predefined fraction and,thus,to potentially design the microstructure of materials according to a specified property-profile.Consequently,flash-annealing poses a unique synthesis route to design materials with,for instance,good biomechanical compatibility.

This study focuses on a quantitative analysis of dislocation accumulation after cold plastic deformation and mechanical properties of FeNiCoCrMn and TiNbHfTaZr high entropy alloys (HEAs) which are single phase fcc and bcc solid solutions, respectively. In order to study the role of compositional complexity from unary to quinary compositions on dislocation accumulation and mechanical properties after plastic deformation, the single solid solution phase forming sub-alloys of the two HEAs were investigated. All studied samples revealed a large plastic deformability under cold-rotary swaging process by 85–90% area reduction without intermediate annealing. The dislocation density of all studied samples, determined by Williamson-Hall method on synchrotron X-ray diffraction patterns, were between 1014 - 1015 m−2 dependent on the alloy composition. The level of dislocation density after plastic deformation is not only affected by the number of constituent element but the lattice distortion and intrinsic properties in terms of stacking fault energy, modulus misfit, and melting point also impact the dislocation storage. The level of dislocation density determines the level of mechanical properties because of a resistance to dislocation motions. The hardness and yield compressive strength of the studied samples are proportional to the level of dislocation density.

The microstructural evolutions in terms of dislocation density, annealing twin density as well as with respect to microstructural changes due to recrystallization and grain growth were investigated in pure Ni, equiatomic FeNiCo alloy, and FeNiCoCrMn high entropy alloy (HEA) during the thermomechanical process. All samples were single phase and showed a face-centered cubic (FCC) lattice structure. This was maintained during thermomechanical processing comprising of cold swaging by 85% reduction of cross-sectional area and subsequent annealing at 800 degrees C. The level of dislocation accumulation during cold swaging increased with the number of constituent elements. The FeNiCoCrMn HEA obtained the highest dislocation density, followed by the FeNiCo and Ni, respectively. After the annealing at 800 degrees C for 0.5 h, all samples achieved the large fraction of recrystallized grains with minor fraction of substructured grains and no deformed grain. The FeNiCoCrMn HEA obtained the smallest recrystallized grain size (similar to 5 mu m) after the annealing at 800 degrees C for 0.5 h. This could be a result of the highest dislocation density generated during cold swaging prior to the annealing. The prolonged annealing at 800 degrees C for up to 24 h led to a grain growth for all the samples, however, at different growth rates. The FeNiCoCrMn HEA revealed the lowest rate of grain growth, but the microstructural changes during the annealing were not significantly different between the FeNiCo and Ni samples. Besides the effect of the number of constituent elements, the type and the combination of constituent elements have an effect on the microstructural evolution during the annealing. (C) 2019 Elsevier B.V. All rights reserved.

Background: Colorectal cancer is the third most common cancer worldwide. There is wide geographic variation in incidence with rates varying ten-fold between high- and low-income countries. This heavy burden can be mitigated given previous research has estimated that nearly half of all colorectal cancer cases could have been prevented through healthier diets and physically active lifestyles. In Canada, there is considerable geographic variation in age-adjusted incidence rates for colorectal cancer between jurisdictions, greater than that seen for many other cancers. These wide variations likely reflect differences in the prevalence of risk factors across provinces and territories. Aim: To describe the extent of the variation in colorectal cancer incidence rates across Canada and the disparities in the prevalence of modifiable risk factors across jurisdictions known to contribute to this burden. Methods: Colorectal cancer incident cases were obtained from the Canadian Cancer Registry; 2014 was used for provinces (except Quebec where 2010 was the most recent year available) and years 2012 to 2014 were combined to achieve more stable rates for the territories, which are much smaller in population. Data on four known modifiable risk factors for colorectal cancer (excess weight, physical inactivity, alcohol intake and low fruit and vegetable consumption) were obtained from the 2015-16 combined Canadian Community Health Survey. Results: Findings suggest that there is a north-south and east-west gradient in colorectal cancer modifiable risk factors in Canada. For instance, the percentage of adults with excess body weight ranged from 56.8% in British Columbia (west) to 73.1% in New Brunswick (east) and the percentage of adults not meeting physical activity guidelines ranged from 31.8% in Yukon (north) to 50.3% in New Brunswick (east). Generally, this pattern also reflects colorectal cancer incidence rates. The highest prevalence of modifiable risk factors and rates of colorectal cancer are typically in the northern (territories) and eastern provinces of Canada. Conclusion: The global burden of colorectal cancer is expected to increase by nearly 60% by 2030; therefore, targeted interventions are needed to ensure there is not a widening gap in colorectal cancer burden worldwide. Based on current knowledge, the most effective approaches to reduce the burden of colorectal cancer include: 1) adopting public policies that make healthy choices easier and create healthier environments where people live, work and play, and 2) continuing emphasis on screening and early detection. Strategic approaches to addressing modifiable risk factors, as well as mechanisms for detecting colorectal cancer before it develops, have the potential to translate into positive effects on population health and less people developing and dying from cancer.

Background:Cancer research is essential in evaluating the safety and effectiveness of emerging cancer treatments, which in turn can lead to ground-breaking advancements in cancer care. Given limited research funding, allocating resources in alignment with societal burden is essential. However, evidence shows that such alignment does not typically occur. The objective of the present study was to provide an updated overview of site-specific cancer research investment in Canada and to explore potential discrepancies between the site-specific burden and the level of research investment.Methods:The 10 cancer sites with the highest mortality in 2015-which included brain, female breast, colorectal, leukemia, lung, non-Hodgkin lymphoma, ovary, pancreas, prostate, and uterus-were selected for the analysis. Information about site-specific research investment and cancer burden (raw incidence and mortality) was obtained from the Canadian Cancer Research Survey and Statistics Canada's cansim (the Canadian Socio-Economic Information Management System) respectively. The ratio of site-specific research investment to site-specific burden was used as an indicator of overfunding (ratio > 1) or underfunding (ratio < 1).Results:The 3 cancer sites with the highest research investments were leukemia, prostate, and breast, which together represented 51.3% of 2015 cancer research funding. Conversely, the 3 cancer sites with the lowest investments were uterus, pancreas, and ovary, which together represented 7.8% of 2015 research funding. Relative to site-specific cancer burden, the lung, uterus, and colorectal sites were consistently the most underfunded.Conclusions:Observed discrepancies between cancer burden and research investment indicate that some cancer sites (such as lung, colorectal, and uterus) seem to be underfunded when site-specific incidence and mortality are taken into consideration.