用循环热处理细化铸造TiAl基合金的显微组织

设计了一种新的循环热处理工艺,并用正交设计试验（Ｌ１６（４５））研究了各热处理工艺参数,即加热速度、保温温度、保温时间、冷却速度和循环次数对铸造ＴｉＡｌ基合金显微组织和显微硬度（ＨＶ５）的影响．结果表明：循环热处理工艺均能不同程度地提高显微硬度,提高的最大幅度达４０％;各因素的影响按大小排列依次为加热速度,保温时间、保温温度、冷却速度、循环次数．利用循环热处理可获得不同类型的显微组织．在正交试验的基础上确定了优化的热处理工艺,并用它获得了细小的显微组织．     

Nontraditional manufacturing technique-Nano machining technique based on SPM

Nano machining based on SPM is a novel, nontraditional advanced manufacturing technique. There are three main machining methods based on SPM, i.e.single atom manipulation, surface modification using physical or chemical actions and mechanical scratching. The current development of this technique is summarized. Based on the analysis of mechanical scratching mechanism, a 5 μm micro inflation hole is fabricated on the surface of inertial confinement fusion (ICF) target. The processing technique is optimized. The machining properties of brittle material, single crystal Ge, are investigated. A micro machining system combining SPM and a high accuracy stage is developed. Some 2D and 3D microstructures are fabricated using the system. This method has broad applications in the field of nano machining.     

铈对压铸镁合金AZ91组织和高温性能的影响

采用Olympus—PMG3型光学显微镜、D／Max 2500PC型X射线衍射仪(XRD)、带有EDAX—Falcon能谱仪(EDS)的JSM-5500LV型扫描电子显微镜(SEM)及AG-10TA型电子万能实验机，研究了Ce对压铸镁合金AZ91显微组织、常温性能及高温(150℃)性能的影响。结果表明：AZ91合金中加入Ce后，形成了新的Al4Ce相，使Mg17Al12(γ)相尺寸减小、数量减少、并由网状分布变得离散分布。Ce对AZ91合金常温性能的影响不大，但显著提高了高温性能。加入1．0％Ce的合金具有最好的显微组织和性能，但是Ce的加入量过高，反而使合金的性能降低。     

马氏体相变过程中形核、失稳及多界面微结构的动力学模拟

材料发生相变的过程中会出现失稳、滞后回线及多界面的微结构等复杂现象，而稳定性的丧失使其动力学方程的求解十分困难。对于形状记忆合金中的马氏体相变，相变过程中材料的等效杨氏模量变为负值，使得传统的动力学方程成为病态的，无法直接求解，必须要进行正则化。而相变的滞后回线与微结构的出现也说明经典的弹性理论不再适用，必须要引入新的能量项以能刻画这些现象。本文在非线性弹性理论的框架下，引入应变梯度界面能和位移非均匀能，利用变分原理建立了材料相变的一维动力学模型。高阶项的引入极大地改善了方程的性质，使数值求解成为可能。计算结果表明，该模型确能较有效地描述相变时的失稳与微结构。     

Material microstructures analyzed by using gray level Co-occurrence matrices

The mechanical properties of materials greatly depend on the microstructure morphology. The quantitative characterization of material microstructures is essential for the performance prediction and hence the material design. At present,the quantitative characterization methods mainly rely on the microstructure characterization of shape, size, distribution,and volume fraction, which related to the mechanical properties. These traditional methods have been applied for several decades and the subjectivity of human factors induces unavoidable errors. In this paper, we try to bypass the traditional operations and identify the relationship between the microstructures and the material properties by the texture of image itself directly. The statistical approach is based on gray level Co-occurrence matrix(GLCM), allowing an objective and repeatable study on material microstructures. We first present how to identify GLCM with the optimal parameters, and then apply the method on three systems with different microstructures. The results show that GLCM can reveal the interface information and microstructures complexity with less human impact. Naturally, there is a good correlation between GLCM and the mechanical properties.     

快速穿水冷却装置对热轧带肋钢筋组织性能的影响

一种新型热轧带肋钢筋轧后快速穿水冷却装置进行了应用.快速冷却后,可以大幅度降低热轧带肋钢筋上冷床温度,同时细化铁素体晶粒直径,抑制晶粒长大,从而提高钢筋的力学性能,收到了很好的效果.     

Sensitivity of the macroscopic elasticity tensor to topological microstructural changes

A remarkably simple analytical expression for the sensitivity of the two-dimensional macroscopic elasticity tensor to topological microstructural changes of the underlying material is proposed. The derivation of the proposed formula relies on the concept of topological derivative, applied within a variational multi-scale constitutive framework where the macroscopic strain and stress at each point of the macroscopic continuum are volume averages of their microscopic counterparts over a representative volume element (RVE) of material associated with that point. The derived sensitivity—a symmetric fourth order tensor field over the RVE domain—measures how the estimated two-dimensional macroscopic elasticity tensor changes when a small circular hole is introduced at the microscale level. This information has potential use in the design and optimisation of microstructures.     

红绿共振互补光变亚波长微结构制作与分析

剖析了双层亚波长光栅微结构的设计及制作原理,提出了一种亚波长微结构设计与制作的新方法,其特点是以矩形亚波长光栅设计微结构,用全息干涉光刻及涂布的方法制作,却不影响设计微结构的共振及光变特性,还能改善反射光的颜色质量。用该方法设计及制作了具有“红绿”共振互补光变效果的亚波长防伪微结构,检验了其共振光变光谱与颜色变化特征。研究表明：制作的全息光栅微结构的共振及光变特征如共振光谱、颜色、光谱峰及峰分裂等与预先设计的相同;矩形亚波长光栅并不是共振的必要条件,其他面形光栅微结构的衍射特性和等效波导若与矩形光栅微结构的相同,则其相关特性相同;用新方法设计及制作亚波长光变微结构的工艺是可行的,既降低了设计微结构的加工难度,又便于用现有的全息生产设备批量生产。     

阜新天然焦的显微结构

本文从生产型煤和型焦的需要出发,研究岩浆变质作用所形成的天然焦炭和高、中变质煤的显微结构.并提出选择粘结剂的三条要求。     

热处理法再生活性氧化铝的微结构研究

采用直接煅烧法再生废弃活性氧化铝,可去除废弃氧化铝中易挥发的组分,并通过再结晶过程使载体重新获得一定的孔结构和比表面,达到再生的目的.探讨了热处理温度与时间对活性氧化铝微结构的影响.用XRD、SEM、BET等方法表征活化后氧化铝的微结构,从而确定最佳的热处理制度.结果表明:再生后的试样均形成2种晶相,分别是(A l2O3)1.333和A l2.85O3.45N0.55,属于立方晶系,Fm3m空间群;最佳的热处理制度为在550℃下保温2 h,其对应的比表面积达242.2 m2/g,平均孔径为7.1 nm,活化后样品的各项性能指标达到采用恩醌法生产双氧水所用的活性氧化铝球的使用要求.