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41.
预变形对X90管线钢显微组织和力学性能的影响 总被引:1,自引:1,他引:0
采用拉伸试验、冲击试验、光学显微镜(OM)、扫描电镜(SEM)、显微硬度测试仪等研究了0.5%~6%预拉伸变形对X90管线钢显微组织及力学性能的影响。结果表明:随着预拉伸变形量的增加,X90管线钢晶粒增大,位错塞积导致强度增加,均匀延伸率下降,呈现典型的加工硬化特点,抗拉强度的增幅要小于屈服强度,屈强比增大;随着变形量的增加冲击吸收功逐渐由291J减小至235J,冲击试样断口的韧窝减小,伴随第二相粒子析出;显微硬度中间层较边缘区增加少,预拉伸在6%时边缘显微硬度为325HV。X90管线钢的预拉伸在4%以内能保证管线钢的正常服役。 相似文献
42.
Ibrahima Ka Ivy M. Asuo Suchismita Basu Paul Fourmont Dawit M. Gedamu Alain Pignolet Sylvain G. Cloutier Riad Nechache 《Small (Weinheim an der Bergstrasse, Germany)》2018,14(38)
The morphology of hybrid organic–inorganic perovskite films is known to strongly affect the performance of perovskite‐based solar cells. CH3NH3PbI3‐xClx (MAPbI3‐xClx) films have been previously fabricated with 100% surface coverage in glove boxes. In ambient air, fabrication generally relies on solvent engineering to obtain compact films. In contrast, this work explores the potential of altering the perovskites microstructure for solar cell engineering. This work starts with CH3NH3PbI3‐xClx, films with grain morphology carefully controlled by varying the deposition speed during the spin‐coating process to fabricate efficient and partially transparent solar cells. Devices produced with a CH3NH3PbI3‐xClx film and a compact thick top gold electrode reach a maximum efficiency of 10.2% but display a large photocurrent hysteresis. As it is demonstrated, the introduction of different concentrations of bromide in the precursor solution addresses the hysteresis issues and turns the film morphology into a partially transparent interconnected network of 1D microstructures. This approach leads to semitransparent solar cells with negligible hysteresis and efficiencies up to 7.2%, while allowing average transmission of 17% across the visible spectrum. This work demonstrates that the optimization of the perovskites composition can mitigate the hysteresis effects commonly attributed to the charge trapping within the perovskite film. 相似文献
43.
Yongbiao Wan Zhiguang Qiu Jun Huang Jingyi Yang Qi Wang Peng Lu Junlong Yang Jianming Zhang Siya Huang Zhigang Wu Chuan Fei Guo 《Small (Weinheim an der Bergstrasse, Germany)》2018,14(35)
Nature has long offered human beings with useful materials. Herein, plant materials including flowers and leaves have been directly used as the dielectric material in flexible capacitive electronic skin (e‐skin), which simply consists of a dried flower petal or leaf sandwiched by two flexible electrodes. The plant material is a 3D cell wall network which plays like a compressible metamaterial that elastically collapses upon pressing plus some specific surface structures, and thus the device can sensitively respond to pressure. The device works over a broad‐pressure range from 0.6 Pa to 115 kPa with a maximum sensitivity of 1.54 kPa?1, and shows high stability over 5000 cyclic pressings or bends. The natural‐material‐based e‐skin has been applied in touch sensing, motion monitoring, gas flow detection, and the spatial distribution of pressure. As the foam‐like structure is ubiquitous in plants, a general strategy for a green, cost‐effective, and scalable approach to make flexible e‐skins is offered here. 相似文献
44.
Electronic Skins: Natural Plant Materials as Dielectric Layer for Highly Sensitive Flexible Electronic Skin (Small 35/2018)
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45.
Liang Zhang Ting Wang Bo Yuan Bin Yu Zhichao Chen 《Advanced Engineering Materials》2023,25(11):2201823
Herein, an innovative powder-cored wire arc additive manufacturing (PC-WAAM) process is proposed to fabricate γ-TiAl thin-walled intermetallic alloy. The metallography, phase composition, and mechanical properties at different thin-wall locations are characterized. The results show that the alternatively distributed layer-like microstructure composed of α2 (Ti3Al) and γ (TiAl) phases is obtained along the building direction. The content of α2 phase exhibits the tendency of decreasing from the bottom to top region. This unique microstructure characteristic is closely related to the typical thermal cycling history during deposition. Moreover, the tensile strength and microhardness of the top region are lower than the middle and bottom region. In general, the current PC-WAAM technique shows promising capability of fabricating γ-TiAl intermetallic alloy with low cost. This work becomes a valuable reference for understanding the evolution mechanism of microstructure and paves the way for the flexible and customized additive manufacturing of γ-TiAl alloy. 相似文献
46.
Isao Kobayashi Yoshihiro Wada Kunihiko Uemura Mitsutoshi Nakajima 《Microfluidics and nanofluidics》2008,5(5):677-687
This study investigated the generation of oil drops using new symmetric and asymmetric through-hole-array devices made of
stainless steel. The through-hole-array devices were built by piling up six stainless-steel plates, each having circular micro-holes
with a diameter of 300 or 500 μm or micro-slots with a shorter line of 300 or 500 μm. Drops were generated by injecting a
dispersed phase (refined soybean oil) via the through-hole array into a compartment filled with a continuous phase (Milli-Q
water solution containing one of two emulsifiers). The drop detachment from symmetric and asymmetric through holes was observed
in real time and analyzed. Uniform oil drops with average diameters of 1.0–4.1 mm and coefficients of variation of typically
less than 6% were generated using symmetric and asymmetric through-hole-array devices. The resultant drop diameters for asymmetric
through-hole arrays were significantly smaller than those for symmetric through-hole arrays. This paper also discusses experimental
results regarding the effects of the microstructure, the dimensions of the through holes, and the type of emulsifier on drop
generation and the resultant drop diameter. 相似文献
47.
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49.
采用搅拌摩擦焊接法焊接了5083-H321铝合金板材,借助光学显微镜、扫描电镜、背散射电子衍射分析仪及取向显微成像分析技术对焊缝与母材的组织进行了对比性研究.结果表明,该合金板材的焊缝无宏观缺陷,焊缝成形区呈现出与母材明显不同的组织特征;搅拌摩擦焊使该合金板材中大量的小角度晶界转化为大角度晶界,母材和焊核区的晶粒尺寸分布范围分别为6-55 μm及15-30 μm,晶粒纵横比分布范围分别为2~8和15-3,焊核区呈现均匀化与等轴化的动态再结晶特征. 相似文献
50.
微量Ag对Al-Cu-Mg合金显微组织与力学性能的影响 总被引:1,自引:2,他引:1
研究了Ag元素对Al-8Cu-0.5Mg合金显微组织、室温及高温力学性能的影响。结果表明:均匀分布在铝基体{001}面和{111}面上共存的θ′和Ω(成分为Al2Cu)沉淀相能对含Ag合金起强化作用;而不含Ag的合金只有θ′一种沉淀相。含Ag合金中小尺寸以及近间距的θ′和Ω沉淀相提高了室温及高温下合金的屈服强度和拉伸强度。然而,与不含Ag的合金相比,由于这种小尺寸及近间距的θ′和Ω沉淀相在变形过程中具有与基体的内在不相容性,含银合金的伸长率降低。 相似文献