飞机刹车钢制骨架校平工艺新技术探索

国内现役飞机刹车主要以钢制刹车为主，刹车修理时通常采用热时效的方法对钢制骨架进行校平修理。本文探索一种新的校平工艺，以振动时效取代热时效的方法来消除校平的残余应力，从而达到热时效的工艺效果。     

2219铝合金单轴拉/压蠕变时效行性行为研究

为研究2219铝合金在蠕变时效成形过程中，不同应力状态（拉/压）对其蠕变行为的影响规律，采用室温拉伸的方法研究了165~185℃内单轴拉/压2219铝合金力学性能的变化。结果表明：最佳蠕变时效时间为11 h；在相同的时效制度下，拉/压应力蠕变变形量均随着温度的升高而增加，拉应力的蠕变变形量始终大于压应力的蠕变变形量；无论是拉/压应力蠕变时效还是无应力常规时效，其时效后的性能均随着温度的升高而降低，然而，拉应力时效后性能的下降幅度最为明显；最后，在时效温度为165℃时，不同应力状态下的各项性能指标均表现为最佳。     

新时效制度处理的2024铝合金塑性性能分析

对由导电率和硬度实验初步确定的２０２４铝合金新时效制度进行了拉伸试验研究，并对拉伸塑性性能试验数据进行了数理统计分析。通过实验研究和分析，证明２０２４铝合金采用新的时效制度，在塑性性能方面满足适航要求。     

新时效制度处理的2024铝合金的静强度分析

由导电率和硬度实验初步确定了２０２４铝合金的新时效制度本文对采用新时效制度处理的２０２４铝合金进行了拉伸试验研究，并对试验数据进行了数理统计分析。通过试验研究和分析，证明了在收音机结构维修中，其静强度是满足适航要求的。     

西飞公司应用振动时效技术的现状及前景分析

通过介绍振动时效的原理、工艺特点及其应用情况，并与热时效进行了对比，进而阐述了振动时效技术的优点及工艺局限性，并就在西飞公司的应用前景进行了分析，指出为提高产品质量和效率，应积极开展振动时效技术的研究。     

不同时效状态3J21合金拉伸性能

文摘在万能拉伸试验机上对大气环境下欠时效态、峰时效态和过时效态3 J21合金的拉伸性能进行研究,并采用金相显微镜、X射线衍射仪对各时效态金相组织及物相进行分析,采用TEM对固溶态、时效态试样及拉伸断口附近形变的显微组织进行分析,采用扫描电镜对拉伸断口进行观察。结果表明,峰时效态3 J21合金的拉伸强度和屈服强度均略高于欠时效态和过时效态合金,但其伸长率略低于欠时效态和过时效态合金;各时效态合金的拉伸断口均为韧窝断口,欠时效态合金断口附近显微组织中滑移线之间的距离最小,峰时效态合金滑移线之间的距离最大,而过时效态合金滑移线之间的距离介于两者之间。     

6156铝合金的人工时效与蠕变时效研究

采用光学显微及透射电子显微、维氏硬度、拉伸力学性能、电导率测试等技术,研究了试验6156铝合金的人工时效与蠕变时效强化规律与微观组织特征.结果表明,在本文试验的温度(155～175℃)-应力(0～200MPa) -时间(8～14h)范围内,采用不同制度的人工时效和蠕变时效样品的力学性能相差不大,但蠕变时效的析出相数量增...     

振动时效工艺及在机床生产中的应用

介绍了振动时效工艺的发展，并通过对振动时效技术的研究和对工艺参数的探讨，指出了该工艺取代热时效工艺的可行性和必要性。     

QBe2合金硬时效的相分析

国内外的铍青铜热处理标准，都把晶界反应量作为控制时效工艺质量的标准之一，但未阐明ＱＢｅ２合金硬时效的显微组织特征和假相，本文系统观察了其金相微观结构，发现其组织中细小、密集的β相，容易被误判为晶界反应量，找出了排除假相的方法，阐明了硬时效的组织特征，为正确判定时效组织提供了依据；并指出，冷变形６２．５％的ＱＢｅ２合金经高温短时时效后，ＧＰ区、γ＂、γ＇相并存，经３００℃时效的γ＂、γ＇相弥散细小，３５５℃时效后，析出相尺寸长大，并出现局部再结晶；冷变形＞８１％的ＱＢｅ２合金，经３８５℃×１．５ｈ时效后，组织已再结晶完毕并出现不连续析出物，使性能恶化。     

新淬火状态铝合金2A12薄板V型弯曲回弹及硬度研究

对采用新淬火自然时效1h、2h、4h、8h12h、24h的铝合金2A12板料分别进行单向拉伸试验测出不同时效时间的材料属性;采用V型弯曲试验测量不同时效时间的回弹;采用钢球坠落试验测量其不同时效时间的硬度变化。针对不同的V型弯曲试验状态进行了有限元模拟计算分析,并与试验结果进行对比分析。     

低膨胀高温合金GH907和GH909的铸态组织及其均匀化处理

本文研究了低膨胀高温合金GH907、GH909铸态组织中偏析的性质,偏析对合金组织的影响,以及消除偏析的方法。     

纳米CaCO3/SiO2核-壳结构复合粒子的制备

采用含有纳米碳酸钙的硅酸钠水性悬浮液在酸性物质作用下，硅酸盐发生水解-缩合反应生成溶胶从而沉积在纳米碳酸钙粒子表面的溶胶沉淀法，制备出具有核-壳结构的纳米碳酸钙／二氧化硅复合粒子。用TEM、IR、xPs、TGA、xRD等方法对复合粒子的大小、形貌、化学组成、结构、热性能及晶型等作了分析和表征。     

Waves in space plasmas: Highlights of a Conference held in Hawaii, 7–11 February 1983

The Conference was called to bring together investigators of magnetospheric plasma waves having frequencies from VLF whistlers and emissions down through ELF and ULF to Pc5 long period pulsations. The emphasis was on the physics and techniques underlying the entire frequency range. Topics included wave electron interactions and electron precipitation, ray tracing and other methods to track down sources of VLF and ULF waves, VLF-ULF relationships, heavy ion effects in ULF propagation, and long period ULF waves.     

铝锂合金热机械处理研究进展

综述了热机械处理对新型铝锂合金强韧化机制影响的研究,深入分析讨论了热机械处理对铝锂合金晶粒结构和沉淀相等显微组织演变规律的影响。通过热机械处理改变主要沉淀相的析出顺序和析出行为,促进基体形成细小、弥散和均匀分布的以δ′,θ″/θ′,T1,S″S′相为主的联合强化组织,抑制晶界沉淀相的析出和长大以及晶界无析出带的宽化,能够显著改善铝锂合金的强度和塑韧性匹配。经过固溶处理基体溶质原子和空位密度显著上升,淬火后形成这些缺陷过饱和固溶体为随后时效析出提供了动力。预变形和预时效促进了基体细小弥散的沉淀相δ′相或G. P.区均匀形核析出,在高温时效调节和稳定沉淀相尺寸和体积分数,获得T1、θ″/θ′和δ′相混合组织。新型和特殊热机械处理调控主要强化相δ′,θ″/θ′,T1相析出比例、尺寸和取向,细化晶粒和优化晶粒结构。最后指出应开发大规格轧制板材和热锻件的应力时效等新型热机械处理工艺,以满足大型航空飞机和重型运载火箭对轻质高性能铝锂合金需求。     

正交设计在沉淀硬化不锈钢热处理研究中的应用

用正交设计法研究固溶温度、固溶时间、调整处理温度和调整处理时间对0Cr17Ni5Mo3沉淀硬化不锈钢力学性能的影响.研究结果表明,在沉淀硬化不锈钢热处理研究中采用正交设计法安排试验,可以用很少的试验量获得主要热处理工艺参数对力学性能影响的规律.     

Ni-Co-Al合金非连续沉淀相变及其对合金力学性能的强韧化作用研究

多元合金中非连续沉淀(Discontinuous Precipitation,DP)的出现通常被认为对力学性能有害。最近研究表明,Ni-Co-Al合金通过非连续沉淀析出过程可以形成双相层状纳米结构,实现“类珠光体型”的强化效果。为了进一步探究非连续沉淀对Ni-Co-Al合金力学性能的影响,总结并讨论了在不同合金成分和热处理条件下,Ni-Co-Al合金的显微组织及力学性能的变化规律。结果表明,Co元素含量的增加以及时效温度的降低有利于非连续沉淀析出,而且接近完全转变的DP组织能有效地提高Ni-Co-Al合金的强度和塑性。通过理论模拟、显微结构表征和力学性能分析,讨论了非连续沉淀的析出行为以及该反应对Ni-Co-Al合金力学性能的强韧化作用机制,指出该处理方法为镍基高温合金的强韧化研究提供了新的思路。     

高强度铝合金显微组织高温同位研究

 利用高压透射电镜对高强度铝合金LC4-CS进行高温同位组织观察,研究合金由完全时效状态快速瞬时加热到300℃过程中的显微组织变化,测定不同温度加热后的性能。试验证明,快速瞬时加热可以将晶间析出和基体沉淀,控制在预期的沉淀序列的不同阶段上。     

Global Imaging of Proton and Electron Aurorae in the far Ultraviolet

The IMAGE spacecraft carries three FUV photon imagers, the Wideband Imaging Camera (WIC) and two channels, SI-12 and SI-13, of the Spectrographic Imager. These provide simultaneous global images, which can be interpreted in terms of the precipitating particle types (protons and electrons) and their energies. IMAGE FUV is the first space-borne global imager that can provide instantaneous global images of the proton precipitation. At times a bright auroral spot, rich in proton precipitation, is observed on the dayside, several degrees poleward of the auroral zone. The spot was identified as the footprint of the merging region of the cusp that is located on lobe field lines when IMF B_z was northward. This identification was based on compelling statistical evidence showing that the appearance and location of the spot is consistent with the IMF B_z and B_y directions. The intensity of the spot is well correlated with the solar wind dynamic pressure and it was found that the direct entry of solar wind particles could account for the intensity of the observed spot without the need for any additional acceleration. Another discovery was the observation of dayside sub-auroral proton arcs. These arcs were observed in the midday to afternoon MLT sector. Conjugate satellite observations showed that these arcs were generated by pure proton precipitation. Nightside auroras and their relationship to substorm phases were studied through single case studies and in a superimposed epoch analysis. It was found that generally there is substantial proton precipitation prior to substorms and the proton intensity only doubles at substorm onset while the electron auroral brightness increases on average by a factor of 5 and sometimes by as much as a factor of 10. Substorm onset occurs in the central region of the pre-existing proton precipitation. Assuming that nightside protons are precipitating from a quasi-stable ring current at its outer regions where the field lines are distorted by neutral sheet currents we can associate the onset location with this region of closed but distorted field lines relatively close to the earth. Our results also show that protons are present in the initial poleward substorm expansion however later they are over taken by the electrons. We also find that the intensity of the substorms as quantified by the intensity of the post onset electron precipitation is correlated with the intensity of the proton precipitation prior to the substorms, highlighting the role of the pre-existing near earth plasma in the production of the next substorm.     

Observations of Magnetospheric Waves and their Relation to Precipitation

Magnetospheric wave observations are discussed from the viewpoint of their potential importance for precipitation of charged particles into the auroral zones. While wave processes are a fundamental part of magnetospheric plasma physics, occurring most of the time in most of the magnetospheric regions, their direct role in and relative importance for auroral precipitation are not easy to assess. The role of the waves varies from one spatial region to another and is very different for electrons and ions. Furthermore, the distinction between wave processes and other precipitation mechanisms is not at all straightforward. This review focuses on four main topics: The problem of diffuse electron precipitation, the recent surprise on the detailed structure of broad-banded electrostatic noise in the plasma sheet boundary layer, ion precipitation through electromagnetic ion cyclotron waves, and the role of low-altitude waves in precipitation. It is concluded that, while the observational status of high-altitude ion cyclotron waves is reasonably good, in most areas more thorough studies of existing data as well as refined observations are very much needed. Successful observational studies are to be carried out jointly with theoretical work as well as with studies on the large-scale context of the often localized wave processes. This is especially important when interests are moving toward more nonlinear phenomena, such as shocks, double layers, or strong quasi-static gradients, where a strict adherence to classical wave concepts is becoming more and more diffuse and less motivated.