用反向传播人工神经网络预测低碳低合金钢的马氏体转变开始温度

根据收集和整理的实验数据，建立了低碳低合金钢的成分与马氏体转变开始温度(M.点)的反向传播(BP)人工神经网络，用这种方法预测了一些钢的M.点，并与用其它经验公式得到的结果进行了比较．结果表明：用人工神经网络能更精确地预测钢的M.点，预测精度明显高于其它线性经验公式．另外用正交实验法设计了几种基准成分的钢，用人工神经网络分析了几种合金元素对M.点的定量影响，计算结果表明，与传统的经验公式表达的信息不同，合金元素的含量与钢的M.点间表现为非线性关系．可以认为，这种非线性关系是由合金元素间复杂的交互作用引起的．     

应用人工神经网络预测有色金属海水腐蚀的长期行为

建立人工神经网络，并利用4个实海暴露站点8年累积的腐蚀数据对其进行训练．在训练成功以后，应用其对合金的16年腐蚀行为进行预测．预测结果与实际结果的误差在20％以内，远比传统的函数回归方法小．尤其对于规律性差，无法成功进行函数回归的腐蚀数据，应用人工神经网络预测却能得到较为准确的结果。     

基于逐步回归分析法的表面粗糙度预测

为减少渗碳钢轴的导磁性对磁粒研磨加工的影响,将磨料贮存于周围镶嵌多个磁极的圆形容器中,使被工件带走的磁性粒子能够在磁极间循环利用,虽然降低了磁性磨料在单个磁极处的自我更新作用,但是能够防止磁性磨料的流失。开展对20CrMnTi材质的轴类零件的试验,以加工时间、工件转速、磁性磨料和研磨液的质量比、磁性磨粒的粒径为自变量,工件表面粗糙度作为因变量,采用逐步回归分析建立表面粗糙度预测模型,通过试验验证预测结果的准确性。结果表明:预测模型的表面粗糙度的相对误差绝对值能够控制在7%以内,具有较好的预测能力。      

合金元素对烧结Nd-Fe-B磁体磁性能的影响

述了两类合金元素(代换元素：Co，Dy或Tb与掺杂元素：M1(低熔点元素)：Cu，Al，Ga，Sn，Ge，Zn等与M2(高熔点元素)：Nb，Mo，W，Zr，Ti，V，Cr等)的添加对烧结Nd-Fe-B永磁合金的显微结构和磁性能的影响。综述了两种合金化方式(传统合金化方式：在熔炼前加入合金元素；晶间合金化方式：在球磨或气流磨前加入合金元素)对烧结Nd-Fe-B磁体显微结构和磁性能的不同影响；最后指出晶间合金化复合添加方式是一种很有前景的生产高性能Nd-Fe-B磁体的方法。     

基于人工神经网络对锆基合金HANA-4和HANA-6回火后硬度的预测

采用人工神经网络方法建立了锆基合金HANA-4(Zr-1.5Nb-0.4Sn-0.2Fe-0.1Cr)和HANA-6(Zr-1.1Nb-0.05Cu)回火参数与硬度的预测模型;利用所建立的网络模型预测不同回火态下材料的硬度。测试结果表明:最大相对误差绝对值是6.8869%,拟合率是0.9991。     

用人工神经网络模型预测钢的奥氏体形成温度

根据收集的实验数据，建立了预测钢的奥氏体形成温度(Ac1和Ac3点)的反向传播人工神经网络模型．用散点图和均方误差、相对均方误差和拟合分值三个统计学指标评价模型的预测性能．人工神经网络预测Ac3和Ac1的三个统计学指标分别为23．8℃，14．6℃；2．89％，2．06％和1．8921，1．7011．散点图和统计学指标均显示：人工神经网络的预测性能优于Andrews公式．此外，用人工神经网络分析了C和Mn的含量对Ac1和Ac3温度的定量影响，计算结果显示，C和Mn含量与Ac3和Ac1点间存在非线性关系，这主要是由于钢中合金元素间存在的相互作用造成的。     

外补偿法改善永磁体温度稳定性的研究进展

本文介绍了外补偿法改善永磁体磁性能温度稳定性的工作原理,综述了近年来外补偿法的应用现状,以及外补偿法对Nd-Fe-B永磁体进行磁性能温度补偿的应用情况和研究状况,阐述了补偿设计中所需的关键材料磁温度补偿合金的合金成分和制备工艺方面的研究进展,提出通过外补偿法使Nd-Fe-B永磁体取代Sm-Co磁体的可能性,指出存在的主要问题是磁温度补偿合金的热磁性能达不到要求,缺乏配套的高性能耐腐蚀的Nd-Fe-B永磁体,磁温度补偿合金与Nd-Fe-B永磁体之间的匹配问题,以及相应的磁路设计、组合磁体的表征方法等.     

基于锆基合金退火参数与硬度的BP神经网络模型

基于Trainrp算法建立锆基合金HANA-4(Zr-1.5Nb-0.4Sn-0.2Fe-0.1Cr)和HANA-6(Zr-1.1Nb-0.05Cu)退火参数与硬度的BP神经网络预测模型。模型输入单元为合金成分、退火温度和退火时间,输出单元为硬度。神经网络为3-7-1结构,动量因子和学习速率均为0.6。以实验结果验证网络的可靠性。预测结果表明,相对误差为7%,相对拟合率R值为0.98534。该模型可为锆基合金退火参数的制定提供参考。网络敏感性分析表明:退火温度和退火时间对网络的精度影响很大,而合金成分则影响很小。     

基于BP神经网络的铸态高熵合金成分-强度预报

对文献报道的铸态高熵合金的成分和压缩断裂强度进行统计,获得了铸态高熵合金成分(元素种类、含量)、强度(压缩断裂强度)的参数,分别以这些数据作为输入和输出,利用BP人工神经网络建立起其间的关系网络模型.研究表明:所建立的网络很好地反映出铸态高熵合金的成分-强度之间的关系并且具有较好的精度,网络模型可用来预测不同成分铸态高熵合金的压缩断裂强度.该网络对铸态高熵合金的体系设计具有有效的指导作用.     

应用人工神经网络建立TC11钛合金化学元素与力学性能关系模型

在TC11钛合金大量实验数据的基础上,应用人工神经网络建立TC11钛合金的化学元素与力学性能关系模型。模型的输入参数包括Al、Mo、Zr、Si、Fe、C、O、N和H共9种化学元素;输出为常规力学性能指标(抗拉强度、屈服强度、延伸率和断面收缩率)。运用未知数据样本对已建立神经网络模型的预测能力进行检验,并以Al、Mo、Zr和C元素为研究对象,利用该模型分析TC11钛合金化学元素对力学性能的影响规律。结果表明:网络的预测值与实验值的相对误差均在10%以内,说明所建立的神经网络预测模型具有较精确的预测能力,而且能够清楚地反映出该合金化学元素与力学性能之间的非线性关系。     

Effects of Post-weld Heat Treatment on Microstructure,Mechanical Properties and the Role of Weld Reinforcement in 2219 Aluminum Alloy TIG-Welded Joints

In as-welded state, each region of 2219 aluminum alloy TIG-welded joint shows diff erent microstructure and microhardness due to the diff erent welding heat cycles and the resulting evolution of second phases. After the post-weld heat treatment, both the amount and the size of the eutectic structure or θ phases decreased. Correspondingly, both the Cu content in α-Al matrix and the microhardness increased to a similar level in each region of the joint, and the tensile strength of the entire joint was greatly improved. Post-weld heat treatment played the role of solid solution strengthening and aging strengthening. After the post-weld heat treatment, the weld performance became similar to other regions, but weld reinforcements lost their reinforcing eff ect on the weld and their existence was more of an adverse eff ect. The joint without weld reinforcements after the post-weld heat treatment had the optimal tensile properties, and the specimens randomly crack in the weld zone.     

The First Phase of the SRIF Industrialized Base in ＂West Area＂ Has Been Put into Operation

After nearly two years＇ tense construction, the first phase of industrialized base of Shenyang Research Institute of Foundry （SRIF）, located at the Tiexi Casting and Forging Industrial Park in the west of Tiexi District, has now been completed and formally put into operation.     

Effect of Rare Earth Doping on Impedance,Modulus and Conductivity Properties of Multiferroic Composites:0.5(BiLa_xFe_(1-x)O_3)–0.5(PbTiO_3)

The Lanthanum-doped bismuth ferrite–lead titanate compositions of 0.5(Bi LaxFe1-xO3)–0.5(Pb Ti O3)(x = 0.05,0.10,0.15,0.20)(BLxF1-x-PT) were prepared by mixed oxide method.Structural characterization was performed by X-ray diffraction and shows a tetragonal structure at room temperature.The lattice parameter c/a ratio decreases with increasing of La(x = 0.05–0.20) concentration of the composites.The effect of charge carrier/ion hopping mechanism,conductivity,relaxation process and impedance parameters was studied using an impedance analyzer in a wide frequency range(102–106Hz) at different temperatures.The nature of Nyquist plot confirms the presence of bulk effects only,and non-Debye type of relaxation processes occurs in the composites.The electrical modulus exhibits an important role of the hopping mechanism in the electrical transport process of the materials.The ac conductivity and dc conductivity of the materials were studied,and the activation energy found to be 0.81,0.77,0.76 and 0.74 e V for all compositions of x = 0.05–0.20 at different temperatures(200–300 °C).     

Quantitative Analysis of the Crystallographic Orientation Relationship Between the Martensite and Austenite in Quenching–Partitioning–Tempering Steels

The orientation relationships(ORs)between the martensite and the retained austenite in low-and medium-carbon steels after quenching–partitioning–tempering process were studied in this work.The ORs in the studied steels are identified by selected-area electron diffraction(SAED)as either K–S or N–W ORs.Meanwhile,the ORs were also studied based on numerical fitting of electron backscatter diffraction data method suggested by Miyamoto.The simulated K–S and N–W ORs in the low-index directions generally do not well coincide with the experimental pole figure,which may be attributed to both the orientation spread from the ideal variant orientations and high symmetry of the low-index directions.However,the simulated results coincide well with experimental pole figures in the high-index directions{123}_(bcc).A modified method with simplicity based on Miyamoto’s work was proposed.The results indicate that the ORs determined by modified method are similar to those determined by Miyamoto’method,that is,the OR is near K–S OR for the low-carbon Q–P–T steel,and with the increase of carbon content,the OR is closer to N–W OR in medium-carbon Q–P–T steel.     

The Mirror with Patterns of Auspicious Animals and Grapes——Exquisite cast mirror and the technology of surface tin-enrichment by rubbing-in and infiltration of tin-rich powder

<正>Bronze mirrors were used by the Chinese people before the introduction of the glass mirror.Only after it was replaced by the glass mirror did the bronze mirror gradually retreat from people's lives.Different styles of bronze mirrors were made in different historical periods,particularly in the Warring States Period,the Han and Tang Dynasties,which were the three peaks of the development of bronze mirror arts in ancient China.The casting techniques were exquisite.The surface of the bronze mirror was smooth and bright enough to reflect one's image,and there were scarcely any casting defects on the mirror surface.On the back of the bronze mirror,there were rich depictions of Arts and Humanities,and the ornamentations were also     

The 9th China International Diecasting Congress & Exhibition

The 9th China International Diecasting Congress ＆ Exhibition was held on July 22-24, 2014 at Shanghai New International Expc Centre. This exhibition was the most successful over the years, with over 6890 visitors and 155 exhibitors, and the exhibition area increased by 30% from 9,500 square meters in 2012 to 12340 square meters. Die casting enterprises from a total of 24 countries and regions, including China mainland, Chinese Taiwan and Hong Kong, South Korea, Japan, Germany, India, Thailand, Malaysia, the United States, Russia, Australia, Iran, Ukraine, Brazil, Colombia, Singapore, Austria, Canada, Croatia, France, Turkey, United Kingdom, Vietnam, attended the congress and exhibition.     

Introduction of the Fluid Control Engineering Institute of Kunming University of Science and Technology

正The Fluid Control Engineering Institute of Kunming University of Science and Technology was set up in 1996.The researches of institute concentrate on electro-hydraulic(pneumatic)servo/proportional control and hydromechatronics.The Institute is committed to research and development of electro-hydraulic control of high-end technical equipment in ferrous metallurgy refining produc-     

RARE METALS Volume Contents

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Antimony Induced Crystallization of Amorphous Silicon

Antimony induced crystallization of PVD (physics vapor deposition) amorphous silicon can be observed on sapphire substrates. Very large crystalline regions up to several tens of micrometers can be formed. The Si diffraction patterns of the area of crystallization can be observed with TEM (transmission electron microscopy). Only a few and much smaller crystals of the order of 1μm were formed when the antimony layer was deposited by MBE (molecular beam epitaxy) compared with a layer formed by thermal evaporation. The use of high vacuum is essential in order to observe any Sb induced crystallization at all. In addition it is necessary to take measures to limit the evaporation of the antimony.     

A CUMULATIVE FATIGUE DAMAGE RULE UNDER THE ALTERNATIVE OF CORROSION OR CYCLIC LOADING

Fatigue damage increases with the applied loading cycles in a cumulative manner and the material deteriorates with the corrosion time. A cumulative fatigue damage rule under the alternative of corrosion or cyclic loading was proposed. The specimens of aluminum alloy LY12-CZ soaked in corrosive liquid for different times were tested under the constant amplitude cyclic loading to obtain S-N curves. The test was carried out to verify the proposed cumulative fatigue damage rule under the different combinations among corrosion time, loading level, and the cycle numbers. It was shown that the predicted residual fatigue lives showed a good agreement with the experimental results and the proposed rule was simple and can be easily adopted.