等通道转角挤压对Mg-Li合金力学性能的影响概述

等通道转角挤压（ECAP）是一种高效率的大塑性变形（SPD）技术,用于生产具有优异性能的超细晶粒（UFG）材料。本文总结了经ECAP加工的各种Mg-Li合金的力学性能、加工参数的影响及其相关机理,为未来提高镁锂合金力学性能提供研究方向与支持。     

海洋工程用钢表面喷涂Zn、Al和Zn-55%Al伪合金涂层的耐蚀性

热喷涂金属涂层是当前海洋环境下钢结构件防腐的首选方法,利用电弧喷涂技术在新型海洋工程结构用钢(Q345B钢)表面制备了Zn-55%Al伪合金热喷涂涂层,并与纯Zn涂层和纯Al涂层的耐蚀性进行了对比。结果表明:纯Zn涂层能提供较好的电化学阴极保护作用,但电化学性能欠佳;纯Al涂层表现出优良的电化学性能,但腐蚀后期产生点蚀;Zn-55%Al伪合金涂层具有更优越的耐蚀性和腐蚀防护性能。     

复合金属板用高强度耐腐蚀聚酯型热熔胶的研制

按照m[氯乙烯醋酸乙烯酯(VC-VAc)]∶m[二月桂酸二丁基锡(DBTDL)]∶m[邻苯二甲酸二丁酯(DBP)]∶m(硬脂酸钙)=50∶3∶4∶1比例配制复合氯醋树脂,然后以此作为聚酯热熔胶的改性剂。结果表明:当w(复合氯醋树脂)=30%(相对于热熔胶而言)时,改性热熔胶的粘接强度为7.6 MPa,Tg提高到91.2℃;改性热熔胶在10%醋酸或40%NaOH溶液中浸泡48 h后未发生剥离现象,其最大粘接强度分别为6.68 MPa和6.39 MPa;经5%NaCl喷雾24 h或10%Na2CO3溶液浸泡48 h后,其性能最接近未浸泡试样;该高性能热熔胶适用于双金属板的热复合。     

等通道转角挤压制备超细晶镁合金腐蚀行为研究进展

镁合金较差的耐蚀性制约着其应用进程,等通道转角挤压(ECAP)可实现镁合金的组织超细化,有望在提高镁合金力学性能的同时改善其耐蚀性。综述了当前ECAP制备超细晶镁合金腐蚀行为的研究进展,通过对纯镁、Mg-Al合金、Mg-RE合金等典型镁材腐蚀行为与机理的分析,初步探索了借助ECAP同时实现镁合金强韧化和耐蚀化的可能途径。     

海洋装备防腐用镁合金牺牲阳极的研究进展

采用牺牲阳极进行大型金属结构的腐蚀防护具有易维护、无需外加电源等诸多优点,现代蓝色经济的发展促进了镁合金阳极在海洋装备防腐中的应用.综述了牺牲阳极的防腐原理及其海洋防腐应用时的性能要求;继而分析了典型镁合金阳极材料的化学组成、性能特点及海洋环境中服役行为的影响因素;探讨了改善镁合金牺牲阳极的途径、新型牺牲阳极材料的发展...     

硅烷膏体浸渍混凝土表面性能研究

为提升混凝土结构耐久性能,在特定环境下必须采用有效地防腐蚀附加措施.其中硅烷浸渍技术作为提高混凝土耐久性方法之一,其应用日益广泛.本研究针对硅烷膏体浸渍对混凝土防水防蚀等方面保护作用,系统研究了硅烷膏体浸渍普通混凝土和海工混凝土后浸渍深度、吸水率、氯化物吸收量降低率、抗碱性能等方面性能.结果表明:硅烷膏体浸渍后形成一定...     

Improving in-vitro biocorrosion resistance of Mg-Zn-Mn-Ca alloy in Hank’s solution through addition of cerium

Two kinds of Mg-Zn-Mn-Ca alloys with and without cerium were designed and fabricated. In-vitro degradation tests and electrochemical evaluations were carried out to compare their biocorrosion behavior in Hank’s solution at 37 oC. After adding cerium, the continuous network distributed Ca2Mg6Zn3 phases in Mg-2Zn-0.5Mn-1Ca alloy(Alloy I) were separated due to the emerging non-continuously distributed Mg2 Ca phase and Mg12 Ce Zn phase. This change led to corrosion acceleration of Mg matrix at the initial stage but also sped up the formation of compact corrosion products for Mg-2Zn-0.5Mn-1Ca-1.5Ce alloy(Alloy II), and therefore enhanced its biocorrosion resistance. Cerium containing Alloy II has the potential to be used as future biomaterials.     

Effect of microstructures on superplasticity of Al-11%Si alloy

Three kinds of Al-11%Si (mass fraction) alloy samples with different processes were produced to investigate the effect of microstructures on its superplasticity. Among them, the as-ECAP sample pressed 16 passes has ultrafine grains (300 nm) and the finest secondary particles. The ECAP-T6 sample, with ECAP 16 passes followed by T6 treatment, has fine secondary particles (3 μm) but the largest grains (8 μm). Contrarily, the T6-ECAP sample, with T6 treatment followed by ECAP 16 passes, has ultrafine grains and the large secondary particles (7 μm). The tensile testing results show that the as-ECAP sample exhibits superplasticity at high strain rate of 5.75×10-1 s-1 due to its fine secondary particles and ultrafine grains. The ECAP-T6 sample, however, does not exhibit superplasticity at the same high strain rate of 5.75×10-1 s-1 because it has relatively large secondary particles and large grains. Remarkably, the T6-ECAP sample does not have superplasticity even at the lower strain rate of 1.15×10-1 s-1, attributing to its comparatively large secondary particles. When most secondary particles are larger than 7 μm, the high strain rate superplasticity could not be obtained even if this sample has ultrafine grains.     

金属基复合材料概述(1)

金属基复合材料是由陶瓷颗粒成纤维（如SiC,Al2O3,TiC,TiB等）增强金属或者合金基体而得到的,具有高的比刚度、比强度、耐磨性和高温性能,且具有可设计性,是一类高性能先进材料,在航空、航天、汽车等领域具有良好的应用前景。东南大学已开发出铝基、镁基、锌基、钛基等多种复合材料,有些已开始应用于汽车发动机。目前,可供应多种金属基复合材料的铸件与型材。     

金属表面改性技术(5)

本文主要从喷丸强化、表面热处理、高能束热处理三方面介绍了当前金属表面改性技术的应用和发展态势 ,指出表面改性技术 ,是充分发挥金属材料潜力、大幅度拓宽其应用领域的一条行之有效的途径。