| 1 | A review and a statistical analysis of porosity in metals additively manufactured by laser powder bed fusion显示文摘Additive manufacturing(AM), or 3D printing, is an emerging technology that “adds” materials up and constructs products through a layer-by-layer procedure. Laser powder bed fusion(LPBF) is a powder-bed-based AM technology that can fabricate a large variety of metallic materials with excellent quality and accuracy. However, various defects such as porosity,cracks, and incursions can be generated during the printing process. As the most universal and a near-inevitable defect,porosity plays a substantial role in determining the mechanical performance of as-printed products. This work presents a comprehensive review of literatures that focused on the porosity in LPBF printed metals. The formation mechanisms,evaluation methods, effects on mechanical performance with corresponding models, and controlling methods of porosity have been illustrated and discussed in-depth. Achievements in four representative metals, namely Ti-6Al-4V, 316L, Inconel 718, and Al Si10Mg, have been critically reviewed with a statistical analysis on the correlation between porosity fraction and tensile properties. Ductility has been determined as the most sensitive property to porosity among several key tensile properties. This review also provides potential directions and opportunities to address the current porosity-related challenges. | Dawei Wang Huili Han Bo Sa Kelin Li Jujie Yan Jiazhen Zhang Jianguang Liu Zhengdi He Ning Wang Ming Yan | 2022 | Opto-Electronic Advances2022，5，10： | 1 |
| 2 | Laser-Induced Recoverable Fluorescence Quenching of Perovskite Films at a Microscopic Grain Scale显示文摘Understanding the fundamental properties of metal-halide perovskite materials is driving the development of novel optoelectronic applications.Here,we report the observation of a recoverable laser-induced fluorescence quenching phenomenon in perovskite films with a microscopic grain-scale restriction,accompanied by spectral variations.This fluorescence quenching depends on the laser intensity and the dwell time under Auger recombination dominated conditions.These features indicate that the perovskite lattice deformation may take the main responsibility for the transient and show a new aspect to understand halide perovskite photostability.We further modulate this phenomenon by adjusting the charge carrier recombination and extraction,revealing that efficient carrier transfer can improve the bleaching resistance of perovskite grains.Our results provide future opportunities to attain high-performance devices by tuning the perovskite lattice disorder and harvesting the energetic carriers. | Yuren Xiang Yameng Cao Wenqiang Yang Rui Hu Sebastian Wood Bowei Li Qin Hu Fan Zhang Jujie He Mozhgan Yavari Jinlai Zhao Yunlong Zhao Jun Song Junle Qu Rui Zhu Thomas P.Russell S.Ravi P.Silva Wei Zhang | 2022 | Energy & Environmental Materials2022，5，4： | 0 |
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