Corrosion behavior of under‐, peak‐, and over‐aged 6063 alloy: A comparative study

The mechanical property of age‐hardenable Al‐alloys is governed by the state of ageing, which determines the microstructure and consequently, their corrosion behavior which is a vital aspect for a number of applications. This article presents a comparative assessment of corrosion behavior of under‐, peak‐ and over‐aged Al‐Mg‐Si alloy. Corrosion characteristics have been determined via immersion tests in 0.1 M ortho‐phosphoric acid solution and intergranular corrosion (IGC) tests. Corroded surfaces are examined by field emission scanning electron micrographs‐energy dispersive spectroscopy and 3D optical profilometer. The obtained results reveal that the corrosion rate at a specific immersion time as well as the depth of IGC increases in the order for under‐, peak‐, and over‐aged states. Irrespective of the state of ageing, corrosion loss increases linearly but the rate of corrosion decreases rapidly with increasing immersion time. The dominant mode of corrosion in under‐aged alloy is identified as localized pitting, while peak‐aged is highly susceptible to IGC in contrast extensive pitting corrosion is observed for over‐aged alloy. The observed differences in corrosion behavior are explained considering characteristics of precipitates. Formation of β (Mg₂Si) in case of over‐aged alloy and presence of inclusions like AlFeMnSi particles are found to accelerate pitting corrosion.     

论老年教育的地位、作用和发展方向

老年教育在社会中具有重要的地位和作用。它是终身教育的重要组成部分,是社会发展的客观需要,是解决老龄问题的重要途径和方法。探讨了随着社会经济的发展和老龄化社会进程的加快,在21世纪老年教育的发展方向。     

高层医院建筑设计探讨——厦门第一医院病房楼

本文通过设计实践探讨了高层医院建筑的相关问题。     

老年人紧急呼救产品设计要素分析

中国已进入老龄化社会,老龄人口基数庞大,老年人问题已然成为社会的焦点。而我国目前社会基础设施、医疗配套设施、社会福利养老保障设施等都不完善,老年产品比较缺乏。尤其是随着经济的发展和人口的流动,空巢老人已成为社会不可忽视的一类群体,紧急呼救产品将会成为一种必需品。本课题通过对老年人紧急呼救产品设计要素进行详细的分析,从而对产品的开发起到一定的帮助和指导作用,为老年人的养老贡献一点力量。     

纳米材料在涂料中的应用

简述了纳米微粒的基本性质，介绍了几种典型的功能纳米材料在涂料中的应用．并探究其对涂料的改性原理．对应用中存在的问题进行了剖析。     

四川老年居住建筑设计的研究范畴建构

文章以老年人居住建筑为研究对象,梳理与研究对象有关的老年人年龄问题、居住建筑以及研究区域定位等词汇并做了明确定位。根据李立新教授的《设计艺术学研究方法》,将研究范畴定位于设计内部研究领域的设计类型、设计原理、设计美学与设计比较,设计外部研究领域的设计社会学、设计伦理学、设计心理学等内容。并针对设计内部研究做出细部研究设计。     

再生剂与老化沥青微观作用机理

采用分子动力学模拟方法,根据老化沥青体系溶解度参数变化规律,研究了再生剂组分对老化沥青相容性的影响;通过体系的相互作用能分析,探讨了再生剂组分对老化沥青再生的作用机理。结果表明,芳香分有助于改善老化沥青的相容性,且芳香分掺量越大改善效果越好;饱和分则刚好相反,这与实验结论相一致。芳香分与老化沥青相互作用能随掺量增大而急剧增大,意味着两者相互吸引作用显著增强,其原因在于静电相互作用能占据主导地位,范德华相互作用能相对较小;然而饱和分与老化沥青的相互作用能随掺量变化不大,其中静电相互作用能和范德华相互作用能几乎各占一半贡献。分子间的静电相互作用能是影响老化沥青再生的主要因素。     

长春市富豪花园老年公共服务设施配建标准评析简

富豪花园是长春市首批花园式小区的代表,拥有完善的配套设施.20年来,随着人口老龄化进程的加速,现有设施已不能满足老年居民的需求.本文基于居家养老的背景下,通过对富豪花园的调研,分析其老年公共服务设施配建现状及未来发展,提出相应的解决措施,完善老年公共服务设施体系,以帮助更多的老年人实现居家养老.     

国有企业文化养老工作初探

在满足老人物质需求的基础上,以追求老人身心上的健康和精神上的愉悦为目标的文化养老是一种较新的养老方式。目前国有企业文化养老面临着认识不到位和投入不足等问题。文章结合企业实际分析了国有企业文化养老的推进方式。     

Effect of precipitation from tweed matrix on the mechanical properties in a metastable beta alloy of Ti-15-3

The effects of aging treatment on the microstructures and mechanical properties of a metastable beta titanium alloy Ti-15-3 (Ti−15V−3Al−3Sn-3Cr) have been investigated with hardness measurements, tensile test, and optical and electron microscopy. Precipitate-free beta structure with average grain size of about 56 μm was obtained after solution treatment at 800°C for 15 min followed by air cooling. Solution treated specimens were aged up to 800 h in the temperature range between 350 and 600°C. The morphology of the precipitates was varied significantly, depending on the aging temperature. The fine aggregates of α precipitates were dominant above 450°C. Peak hardness values were maintained up to 800 h at 500°C, which showed the superior thermal stability of α precipitates. Tensile strength increased up to 1600 MPa along with the decrease of elongation after aging at 350 and 400°C.