SiCp／Al复合材料高等静压下的性能研究

利用带小孔的恒定高压发生装置，通过高压拉伸、压缩及模锻试验，研究了ＳｉＣｐ／ＡｌＭＭＣ在高等静压下的性能及其随压力变化的规律。研究表明，ＳｉＣｐ／Ａｌ ＭＭＣ在室温高等静压下可进行大变形，得到质量优良的零件，认为高压变形是难变形ＭＭＣ成形的有效途径之一。     

MgLiAl／SiCw复合材料组织与性能的研究

采用真空浸渗法制备了ＭｇＬｉＡｌ／ＳｉＣ复合材料，系统研究了不同基体合金成分的ＭｇＬｉＡｌ／ＳｉＣ复合材料组织，性能及界面结构。研究结果表明，ＭｇＬｉＡｌ／ＳｉＣ复合材料界面结合良好，没有界面反应物。复合强化可明显提高ＭｇＬｉＡｌ合金的抗拉强度和弹性模量。     

Cu,Fe,Mn对压铸AlSi9Cu3性能影响

本文通过对压铸ＡｌＳｉ９Ｃｕ３中合金元素Ｃｕ,Ｆｅ,Ｍｎ正交试验,研究了Ｃｕ,Ｆｅ,Ｍｎ合金元素对压铸铝合金ＡｌＳｉ９Ｃｕ３的力学性能影响。     

我国热作模具钢性能数据集(续ⅩⅢ)

(1 4 )　 5Ｃｒ4Ｍｏ3ＳｉＭｎＶＡｌ钢 ( 0 1 2Ａｌ)5Ｃｒ4Ｍｏ3ＳｉＭｎＶＡｌ钢系属基体钢 ,是一种空冷硬化型的热作和冷作模具兼容的钢种 ,已列入ＧＢ12 99标准。该钢也是在 4Ｃｒ3Ｍｏ3Ｖ钢的基础上重新调整合金元素 ,添加Ｓｉ、Ｍｎ、Ａｌ等元素进一步合金化。与 3Ｃｒ2Ｗ 8Ｖ钢相比不含钨 ,但钼、铬、锰、钒、硅及铝的含量明显提高。 5Ｃｒ4Ｍｏ3ＳｉＭｎＶＡｌ钢6 0 0～ 10 0 0℃的抗氧化性、80 0℃和 910℃的热磨损性能、保持 35ＨＲＣ的热稳定性以及 75 0℃的高温硬度均优于 3Ｃｒ2Ｗ 8Ｖ钢。同样 ,其室温拉伸强度、6 0 0～ 10 0 …     

Al—Si复合材料内在组分对润滑磨损性能的影响

本文研究了硅酸铝纤维增强Ａｌ－Ｓｉ复合金复合材料在润滑状态下磨损性能,结果表明,Ａｌ－Ｓｉ复合材料的耐磨性优于基体合金,随纤维体积分数增加,复合材料耐磨性增加。基体合金Ｓｉ含量对复合材料耐磨性没有明显影响Ａｌ－Ｓｉ合金中加入Ｍｇ元素,可显著提高其复合材料的耐磨性。     

3Al2O3.2SiO2f／Al—Si复合材料磨损机理

本文通过复合材料磨面，磨屑及亚表层的ＳＥＭ特征分析，研究了３Ａｌ２Ｏ３．２ＳｉＯ２ｆ／Ａｌ－Ｓｉ复合材料的润滑衣干滑动磨损机理。润滑状态下复合材料的耐磨性大大优于Ａｌ－Ｓｉ合金，其磨损为纤维断裂与剥落及磨粒磨损；而复合材料在干滑动条件下的耐磨性反而稍差于Ａｌ－Ｓｉ合金，其磨损为粘着磨损，磨粒磨损和层离剥落。     

锌铝合金和铝青铜摩擦磨损特性的研究

研究了锌铝合金ＺＡ－Ｓｉ和铝青铜ＺＣｕＡｌ１０Ｆｅ３在２０号机油润滑条件下的摩擦磨损特性。结果表明：在一定的条件下，ＺＡ－Ｓｉ合金的耐磨性能和磨合性能均明显优于ＺＣｕＡｌ１０Ｆｅ３合金；二种合金的磨损机制主要是犁削，辗压和粘着，ＺＡ－Ｓｉ合金的粘着磨损具有延缓性和失效性的双重特性。     

碳化硅颗粒增强铝基复合材料液态模锻工艺研究

采用半固态搅拌熔炼方法，通过对ＳｉＣ颗粒进行适当的预处理，在基体合金中加入适量的合金元素以及合理控制搅拌温度，搅拌速度及时间等参数，使ＳｉＣ颗粒与铝合金溶液得到了良好的浸润与复合。在此基础上用液态模锻工艺制备了组织致密，颗粒分布较均匀，性能较理想的ＳｉＣｐ／Ａｌ复合材料。用该方法制造复合材料工艺简单，制造成本低，可用于批量生产。     

陶瓷与灰铸铁在水润滑条件下滑动摩擦学特性的研究

在Ｍ－２００环一块磨损试验机上研究了蒸馏水润滑条件下Ｓｉ３Ｎ４、Ａｌ２Ｏ３陶瓷与灰铸铁（ＨＴ）配副时的滑动摩擦磨损特性，并与这两种陶瓷和０．８％Ｃ钢（Ｔ８）配副相对比；在扫描电镜（ＳＥＭ）下对磨损后的试样表面进行了形貌观察和能谱分析。结果表明：Ｓｉ３Ｎ４／ＨＴ的摩擦系数最小，而且Ｓｉ３Ｎ４与ＨＴ的磨损率均比Ｓｉ３Ｎ４与Ｔ８配副时低得多，其原因是由于在灰铸铁表面形成了一层含石墨的氧化膜；Ａｌ２Ｏ３／ＨＴ与Ａｌ２Ｏ３／Ｔ８的摩擦系数差别不大，但灰铸铁的磨损体积小于Ｔ８。这是由于当Ａｌ２Ｏ３与ＨＴ配副时，很难在ＨＴ表面形成含石墨的表面膜，但ＨＴ中的石墨膜减轻了Ｆｅ向Ａｌ２Ｏ３表面的转移从而降低了磨损。     

Al-Si 16%合金的过热温度与结晶行为

研究了不同过热温度对Ａｌ－Ｓｉ１６％结晶组织的影响，发现当过热温度超过９００℃后，试样中的初晶硅尺寸与数目大量增加，共晶硅的尺寸变小。ＤＳＣ分析表明，一定程度的过热增加了Ａｌ－Ｓｉ１６％的结晶潜热。液态Ｘ射线研究发现，在９００℃以下，Ａｌ－Ｓｉ１６％的平均配位数比相同温度纯铝低，而在９００℃以上，合金的平均配位数要高。１２５０℃温度过热后，合金熔体在液相线上方就已出现与硅晶态相对应的衍射峰。过热温度对结晶行为的影响可用Ａｌ－Ｓｉ１６％熔体中Ａｌ－Ｓｉ原子团在较高过热温度下向Ｓｉ－Ｓｉ原子集团转化的机制来解释。     

锻造液压机生产过程能耗分布规律研究

针对锻造液压机能耗高、能量利用率低的问题,研究其正常生产工况下的能耗分布规律。以16 MN 阀控锻造液压机为研究对象,利用AMESim建立其仿真模型,并通过位移压力仿真曲线验证仿真模型的正确性,基于该仿真模型对锻造液压机一个工作循环中的能量利用情况进行仿真研究,获得能耗分布规律。仿真结果表明:在阀控锻造液压机的正常生产工况下,负载有用功在整个能耗中占比小于10%,溢流能耗和节流能耗在系统中造成了巨大的能量损失,通过改进液压系统设计、控制液压系统阀的开启规律可以提高压机能量利用率。     

轴径零件温-冷精锻综合成形工艺及有限元仿真

温 -冷精锻综合成形是一种先进的金属塑性加工工艺 ,近年来在汽车工业中得到了广泛应用 ,并有取代传统的热锻成形的趋势。汽车后轴径是汽车工业中的典型锻件。本文分析了该零件的精锻加工特性 ,建立了其温 -冷精锻成形的有限元模型 ,根据有限元仿真结果确定了该零件的温 -冷精锻综合成形工艺的参数     

新型Cr12V钢在不同温度下的变形性能

对高碳高铬系列中的新钢种Cr12V钢在不同温度和不同速度下作一系列镦粗试验,并得出相应的变形曲线和基本理论的关系式。通过试验证明,所得结论准确,为该新钢种的锻造规范提供了理论和实践依据。     

新型马氏体不锈钢1Cr10Co6MoVNbN热加工工艺研究

1Cr10Co6MoVNb是一种新型马氏体热强不锈钢,用于某发动机高压压气机转子、盘、叶片和密封圈等重要部件,是国产化研究的重要材料。通过分析计算锻造和装炉温度、加热速度、保温时间等参数,制订出理想的锻造加工工艺,并在进口2 000t快锻机上进行了锻造成型工艺试验。结果表明,制订的锻造生产工艺合理可行,钢材锻后具有良好的低倍、断口组织,淬回火状态下具有良好的综合力学性能,超声波探伤100%达到技术要求,满足了国产化用材的需要。     

Isogeometric topology optimization based on energy penalization for symmetric structure

We present an energy penalization method for isogeometric topology optimization using moving morphable components (ITO–MMC), propose an ITO–MMC with an additional bilateral or periodic symmetric constraint for symmetric structures, and then extend the proposed energy penalization method to an ITO–MMC with a symmetric constraint. The energy penalization method can solve the problems of numerical instability and convergence for the ITO–MMC and the ITO–MMC subjected to the structural symmetric constraint with asymmetric loads. Topology optimization problems of asymmetric, bilateral symmetric, and periodic symmetric structures are discussed to validate the effectiveness of the proposed energy penalization approach. Compared with the conventional ITO–MMC, the energy penalization method for the ITO–MMC can improve the convergence rate from 18.6% to 44.5% for the optimization of the asymmetric structure. For the ITO–MMC under a bilateral symmetric constraint, the proposed method can reduce the objective value by 5.6% and obtain a final optimized topology that has a clear boundary with decreased iterations. For the ITO–MMC under a periodic symmetric constraint, the proposed energy penalization method can dramatically reduce the number of iterations and obtain a speedup of more than 2.     

水平连续铸造球墨铸铁塑性变形的研究

本文研究了不同成分的砂型铸造和水平连续铸造球铁棒材的塑性性能。结果得出,对于普通成分的球铁,铸造方式对压缩变形率影响不大,但对合金球铁,连续铸造棒材的高温塑性要优于砂型铸造。连续铸造棒材可以自由锻造成各种形状,可以模锻成球。可利用锻造后的余热进行热处理,经盐浴等温后,可达σ b=1420MPa,δ=8.7%,α K=118J/cm2的优异综合性能。连续铸造棒材的成分偏析小。锻压后,内部的石墨变成条状;铁素体沿石墨分布呈相应条状,并且数量增多。     

Microscopy under pressure--an optical chamber system for fluorescence microscopic analysis of living cells under high hydrostatic pressure

High hydrostatic pressure (HHP) becomes more and more interesting for life science research, since it can be employed to inactivate various cells. To directly monitor "cells under pressure," the development of an optical high-pressure chamber is required. Therefore, an optical pressure chamber that can be used for up to 300 MPa was constructed. This chamber has already been described as a tool for in situ observation of dynamic changes of microscopic structures in bright field as well as phase contrast. In combination with an inverted microscope, we obtained brilliant microscopic color pictures with an optical resolution more than 0.56 microm. Here, we demonstrate the capabilities of the HHP cell, in combination with epifluorescence microscopy. Using a nonadherent human B-cell line (Raji, ATCC CCL 86), stained with the fluorescent dyes propidium iodide, Hoechst 33342, or dihexyloxacarbocyanine iodide, we were able to show that the system is suitable to perform fluorescence microscopic analyses, with pressures up to 300 MPa, with viable mammalian cells.     

Hot shape forging of gas turbine disk using microstructure prediction and finite element analysis

The Waspaloy, a Ni-based superalloy, has been widely used for forging material of gas turbine disk since it requires the high tensile strength at high temperature and good resistance to low cycle fatigue. The purpose of this study is to develop a forging process of turbine disk that satisfies the hot deformation characteristics of Waspaloy. Generally, the hot forging of superalloy has been subjected to isothermal forging since the available temperature range of forging is narrow. However, the non-isothermal forging was used to make a turbine disk in this study. Therefore, the analyses of temperature variation and deformation behavior of the material were important to obtain the sound forging products. The hot compression test was carried out to know formability at high temperature and microstructure evolution during hot deformation. In order to define the optimum forging conditions including material temperature, strain rate, strain, microstructure evolution and forging load, the commercial finite element analysis code was used to simulate the forging procedure of turbine disk. The hot forged turbine disk was heat-treated for obtaining the high temperature properties. The cut-off tests on the heat-treated forged disks were carried out. Experimental results were compared with the simulation results by FE analysis. Test results were in good agreement with the simulations. This study shows that the superalloy turbine disk can be manufactured by the semi-closed die forging.     

一种新型大型水压机立柱应力测试系统

以实现大型水压机特殊环境下立柱应力的高可靠性监测为目的,提出一种新型的水压机立柱应力测试系统。该系统基于"测位式"应力测试思想,利用非接触式微位移传感器测量立柱的微变形,通过应力-应变关系间接求得立柱应力。基于工业现场总线通讯技术,改传统模拟式系统为数字式系统,实现水压机立柱应力测试信号的数字化远距离传输。对新方法进行了系统的试验研究,并实施了工程应用,结果表明,新方法能够替代传统的电阻应变片应力测试方式,实现水压机特殊环境下的立柱应力高可靠性监测功能。最后根据试验研究结果,提出了该方法在实际应用中的若干建议。     

Precision forging technology for aluminum alloy

Aluminum alloy is a preferred metal material for lightweight part manufacturing in aerospace, automobile, and weapon industries due to its good physical properties, such as low density, high specific strength, and good corrosion resistance. However, during forging processes, underfilling, folding, broken streamline, crack, coarse grain, and other macro- or microdefects are easily generated because of the deformation characteristics of aluminum alloys, including narrow forgeable temperature region, fast heat dissipation to dies, strong adhesion, high strain rate sensitivity, and large flow resistance. Thus, it is seriously restricted for the forged part to obtain precision shape and enhanced property. In this paper, progresses in precision forging technologies of aluminum alloy parts were reviewed. Several advanced precision forging technologies have been developed, including closed die forging, isothermal die forging, local loading forging, metal flow forging with relief cavity, auxiliary force or vibration loading, casting-forging hybrid forming, and stamping-forging hybrid forming. High-precision aluminum alloy parts can be realized by controlling the forging processes and parameters or combining precision forging technologies with other forming technologies. The development of these technologies is beneficial to promote the application of aluminum alloys in manufacturing of lightweight parts.