最终形变热处理工艺对Al-5.2Mg-3.1Zn(wt.%)铝合金组织性能的影响

本文深入研究了最终形变热处理工艺对Al-5.2Mg-3.1Zn铝合金组织性能的影响。通过维氏硬度测试研究了变形工艺对最终形变热处理最终时效工艺的影响。通过金相观察和透射电镜观察发现经过最终形变热处理的板材内部存留大量的位错结构和纤维状组织,且其含量取决于板材的变形工艺。通过板材的力学性能和晶间腐蚀性能研究发现：(1)变形温度的提高会降低板材的强度,但会提高板材的延伸率;而变形量的作用则恰恰与之相反;(2)提高变形温度和变形量都有利于提高板材的抗晶间腐蚀性能。     

Interfacial characteristics of Zn/AZ31/Zn clad sheets fabricated by hot roll-bonding and annealing

The Zn/AZ31/Zn tri-layer clad sheets are prepared by hot roll-bonding technology and post-roll annealing in this study and the interfacial microstructure, mechanical and corrosion properties are investigated. The annealing temperature can influence the interfacial bonding behaviour. Upon annealing at 200°C, a good metallurgical bonding interface composed of Mg₄Zn₇ and MgZn₂ phases is obtained. A higher temperature (300°C) can induce the precipitation of the brittle Mg₂Zn₁₁ phase at the interface. The clad sheets annealed at 200°C can attain the maximum bonding strength among all the clad sheets investigated. Importantly, the corrosion rate can be obviously reduced by cladding pure Zn layer on both sides of AZ31 alloys, which provides another effective method to improve the corrosion resistance of magnesium alloys.     

Al-Zn-Mg-(Cu)合金抗应力腐蚀性能影响因素分析

从合金成分、热处理制度以及显微组织特征等方面对如何提高7xxx系铝合金抗应力腐蚀性能进行了系统的分析,重点阐述了影响合金抗应力腐蚀性能的本质因素——GBP、MPT、PFZ、晶界原子偏聚等。同时提出了合理可行的提高7xxx系铝合金抗应力腐蚀性能的解决途径,为新一代超高强铝合金的成分设计和工艺优化提供了重要的参考。     

小波分析在地球物理勘探中的应用

小波分析引入了多尺度分析思想，可以对静态效应和深部异常，局部异常和区域异常，信号和噪声进行识别和分离。基于小波变换的特性，作者在频率域电磁测深静态效应的自动识别和压制、重磁异常分离的高精度方法、电阻率函数的奇性分析和深度反演、地震波速反演成像和噪声压制等方面成功地应用了小波分析理论     

中国古代工程建筑特色与管理思想

中华民族具有五千年悠久的发展历史,在此过程中保留下来的古代工程和建筑是对中国古代文明的真实反映,是中国古代人民智慧结晶和思想精髓所在,体现了中华民族传统的思想观念。本文列举了古代中国具有代表性的工程和建筑,阐述了他们的工程技巧和建筑特征,在此基础上总结了中国古代工程和建筑的特点,并进一步分析了古代工程管理思想的精髓,即“以人为本”与“天人合一”。本文基于我国工程和建筑发展历史、及其特点的研究,目的是为了把握工程管理的本质特征,为发展现代工程管理事业提供基础支撑。     

广域电磁法在湘西北页岩气探测中的应用

将广域电磁法应用于湘西龙山地区的碳质页岩探测,揭示了该区碳质页岩的含碳量较高,相对上、下地层显示为低阻的特征。采用自主研发的“重磁电三维反演成像解释一体化系统”进行广域电磁法数据处理,获得了地下电性体真实的电阻率特征,基本查明龙山地区碳质泥页岩层位的电性分布规律。表明广域电磁法是获取碳质页岩分布范围和埋深的有效探测手段。     

固溶时效处理对TB3钛合金冷镦紧固件组织与性能的影响

研究了TB3钛合金紧固件冷镦成形前固溶处理、冷镦后时效处理过程中的组织与性能变化。结果表明,TB3钛合金紧固件的合理工艺为820 ℃保温30 min空冷（固溶）+冷镦成形+650 ℃保温300 min空冷（时效）。采用合理的固溶时效处理工艺试制了TB3钛合金M5×15内六角螺钉,并对其进行了力学性能测试,抗拉强度达到1238.2 MPa,断后伸长率达到6%,满足钛合金紧固件技术要求。     

Microstructure and mechanical properties of spray-formed AZ91 magnesium alloy

The AZ91 magnesium alloy, preformed with complete shape, has been prepared using spray forming technology under a protective atmosphere. The microstructure and mechanical properties have been investigated. Initially, a homogeneous and equiaxed-grain structure with average grain size of 20 μm was obtained. The tendency for segregation of the divorced eutectic β(Mg₁₇Al₁₂) phase towards the grain boundary was greatly reduced. Further grain refinement was attributed to dynamic recrystallization during extrusion processing. When solution treated at 415 °C and aged at 175 °C, two kinds of β(Mg₁₇Al₁₂) precipitates are formed: the majority are lamellar discontinuous precipitates, in addition to a small amount of dispersed continuous precipitates. The average tensile ultimate and yield strength of the spray-formed and extruded AZ91 magnesium alloy samples were 435 MPa and 360 MPa with a room temperature elongation of 9.2%, indicating an enhanced combination of toughness and strength.     

DUAL-FREQUENCY IP

The dual-frequency(DF)IP is a new kind of frequency domain IP method.Not only is thedual-frequency current transmitted simultaneously but the electric potential difference due to dualfrequency current is measured synchronously.This paper discusses the principle and charateristicof DF current, DF current can be formed by two rectangular currents which must be coherent orelse false Percent Frequency Effect(PEE)will occur.DF currents with different waveforms areequivalent in the ability of detecting IP anomalies.Unstable current has much less effect of DFIP than on conventional variable frequency method;in fact,there is no need to stabilize currentin DF IP method.There are many differences between harmonic contents of DF current and thatof rectangular wave used in variable frequency method,but theoretical analysis,labaratory mod-eling and field data all show that the anomalies of both DF and variable frequency method are sim-liar in character and close in value.DF IP can match variable frequeney IP and time domain IPin the ability of detecting IP anomaly,furthermore,dual-frequency IP measurements are morerapid,more accurate and more simple in operation.     

NiAl基金属间化合物研究现状与前景

介绍了ＮｉＡｌ基金间化合物研究的现状与前景。ＮｉＡｌ由于具有高熔点、低密度和良好的抗氧化性等性能而被认为是下一代的高温结构材料，然而ＮｉＡｌ在室温时塑性低和高温时强度低限制了它作为工程材料的应用。对ＮｉＡｌ的晶体结构和缺陷、力学性能进行研究，采用合金化、控制显微结构和改进加工技术等方法使ＮｉＡｌ的室温塑性和高温强度都得到了提高。