Formation mechanism of inherent spatial heterogeneity of microstructure and mechanical properties of NiTi SMA prepared by laser directed energy deposition

Microfluidic devices are composed of microchannels with a diameter ranging in ten to a few hundred micrometers. Thus, quite small (10-9 to 10-18 litres) amount of liquid can be manipulated by such a precise system. In the past three decades, significant progresses in materials, microfabrication, and various applications have boosted the development of promising functional microfluidic devices. In this review, the recent progresses on novel microfluidic devices with various functions and applications are presented. First, the theory and numerical methods for studying the performance of microfluidic devices are briefly introduced. Then, materials, and fabrication methods of functional microfluidic devices are summarized. Next, from the viewpoint of the applications of the microfluidic devices, the recent significant advances in heat sink, clean water production, chemical reactions, sensor, biomedical field, capillaric circuits, flexible and wearable electronic devices, microrobotics, etc., in turns are then highlighted. Finally, personal perspectives on the challenges and future developments of functional microfluidic devices, aiming to motivate researchers from the fields of engineering, materials, chemistry, mathematics, physics, etc. working together to promote further development and applications of functional microfluidic devices, for the specific purpose of carbon neutrality are provided.

Section: D Printing Methodsmentioning

confidence: 99%

Functional microfluidics: theory, microfabrication, and applications

Xie,

Zhan,

et al. 2024

“…It is of essential guiding significance for the further completion and evolvement [210,[245][246][247] of IPDed AM technologies to systematically summarize the quantitative relationship between the interaction of mechanical deformation force (or thermal + force) and material melting heat, as well as the clarification of IPD induced recrystallization, nucleation, phase transformation and strength-ductility synergy mechanism of the subsequent deposition layer according to the different interface contact degrees. In the aspect of thermodynamics interaction [246,248], the quantified analysis and comparison of the phase transformation, second phase precipitation and annihilation, secondary heat input and PD rebound of the identical metalbased materials under IPDed AM processes with different interface contact degrees and discrepant metal-based materials under IPDed AM processes with identical interface contact degree still require further completeness and supplement, thus improving the basic database of thermodynamic interaction processes.…”

Section: Mechanism Clarificationmentioning

confidence: 99%

Performance-control-orientated hybrid metal additive manufacturing technologies: state of the art, challenges, and future trends

Lv,

Liang,

et al. 2024

Metal additive manufacturing (AM) technologies have made significant progress in the basic theoretical field since their invention in the 1970s. However, performance instability during continuous processing, such as thermal history, residual stress accumulation, and columnar grain epitaxial growth, consistently hinders their broad application in standardized industrial production. To overcome these challenges, performance-control-oriented hybrid AM (HAM) technologies have been introduced. These technologies, by leveraging external auxiliary processes, aim to regulate microstructural evolution and mechanical properties during metal AM. In this context, HAM technologies for molten pool regulation and solidified material deformation are identified as energy field-assisted AM (EFed AM, e.g., ultrasonic, electromagnetic, heat, etc.) technologies and interlayer plastic deformation-assisted AM (IPDed AM, e.g., laser shock peening, rolling, ultrasonic peening, friction stir process, etc.) technologies, respectively. A detailed and systematic review of performance-control-oriented HAM technologies is then provided. This review covers the influence of external energy fields on the melting, flow, and solidification behavior of materials, and the regulatory effects of interlayer plastic deformation on grain refinement, nucleation, and recrystallization. Furthermore, the role of performance-control-oriented HAM technologies in managing residual stress conversion, metallurgical defect closure, mechanical property improvement, and anisotropy regulation is thoroughly reviewed and discussed. The review concludes with an analysis of future development trends in EFed AM and IPDed AM technologies.

“…As is well-known, it is the complex thermal history of the AM process that contributes to the unique microstructure [43][44][45][46][47][48][49]. The microstructure of GW-series alloys prepared by conventional casting and AM processes such as wire-arc DED and L-DED is compared in figure 16.…”

Section: Unique Microstructure Of Wire-arc Dedmentioning

confidence: 99%

Revealing precipitation behavior and mechanical response of wire-arc directed energy deposited Mg-Gd-Y-Zr alloy by tailoring aging procedures

Li,

Fang,

Zhang

et al. 2024

Mg-Gd-Y-Zr alloy, as a typical magnesium rare-earth (Mg-RE) alloy, is gaining popularity in the advanced equipment manufacturing fields owing to their noticeable age-hardening properties and high specific strength. However, it is extremely challenging to prepare wrought components with large dimensions and complex shapes because of the poor room-temperature processability of Mg-Gd-Y-Zr alloy. Herein, we report a wire-arc directed energy deposited (DED) Mg-10.45Gd-2.27Y-0.52Zr (wt.%, GW102K) alloy with high RE content presenting prominent combination of strength and ductility, realized by tailored nanoprecipitates enabled by optimized heat treatment procedures. Specifically, the solution-treated sample exhibits excellent ductility with an elongation (EL) of 14.6 ± 0.1%, while the aging-treated sample at 200 ℃ for 58h achieves an ultra-high ultimate tensile strength (UTS) of 371 ± 1.5 MPa. Besides, the aging-treated sample at 250 ℃ for 16h attains a good strength-ductility synergy with an UTS of 316 ± 2.1 MPa and an EL of 8.5 ± 0.1%. Particularly, the evolution mechanisms of precipitation response induced by various aging parameters and deformation behavior caused by nanoprecipitates type were also systematically revealed. The excellent ductility resulted from coordinating localized strains facilitated by active slip activity, the ultra-high strength should be ascribed to the dense nano-β' hampering dislocation motion, while the shearable nano-β1 contributed to the good strength-ductility synergy. This work thus offers insightful understanding into the nanoprecipitates manipulation and performance tailoring for the wire-arc DED preparation of large-sized Mg-Gd-Y-Zr component with complex geometries.