稀土变质ZA—27合金的组织与机械性能

稀土变质ＺＡ—２７合金的组织与机械性能合肥工业大学苏勇一、前言高铅锌基合金（特别是ＺＡ－２７合金）作为一种结构材料和耐磨减摩材料．无论是力学性能、工艺性能．还是经济性、都具有很大的优越性．可以与一些高强度铸铁、青铜和铝合金相媲美。但该合金由于凝固温度...     

新型铝基滑动轴承合金的性能与应用

研究了新型铝基滑动轴承合金(TZS88)的成分和性能，用以取代ZCuSn6Zn6Pb3锡青铜制造整体材质的轴瓦、轴套等机械零件。试验和生产实践证明，新合金已成功地应用于低速重载或较高温度、较高滑动速度等工况条件的滑动轴承．取得很好的经济效益。     

高铝锌基合金的力学性能与显微组织研究

研究了五种不同铝含量(30％～50％)的锌基合金在室温、100℃和200℃时的力学性能及影响因素。结果表明：高铝锌基合金的组织为初生α‘相枝晶和α与η相的共析体及少量ε相、Mn相和共晶体等。随着合金中含铝量的增多，α‘相枝晶增多，共析体减少。在室温下ZA45具有较高的力学性能；ZA50具有较高的高温力学性能。     

用混合稀土改善高铝锌基合金耐磨性的研究

探讨了在ZA12合金中添加了富铈混合稀土后组织及耐磨性的变化。实验结果表明：在ZA12合金中加入微量RE能细化晶粒，提高硬度，合金耐磨性改善。在不同的稀土加入量中，0．23%RE加入量的ZA12合金耐磨性最好。     

滑动轴承合金耐磨性能规律的探讨

采用MPX-2000型销-盘式摩擦磨损试验机对ZA30、ZCuSn6Zn6Pb3、ZCuAl10Fe3、ZCuSn10P1这4种滑动轴承合金在不同载荷、不同润滑条件下的耐磨性能进行了对比试验,并在扫描电子显微镜上观察了磨损表面形貌,探讨了磨损机理。结果表明：当4种合金都处于低位磨损状态时,其耐磨性的次序为：ZA30〉ZCuSn10P1〉ZCuSn6Zn6Pb3〉ZCuAl10Fe3;随着载荷、润滑等工况条件的变化,合金会由低位磨损状态（磨粒磨损）向剧烈磨损状态（粘着磨损）转化,其转化次序为ZCuSn6Zn6Pb3〉ZCuSn10P1〉ZA30〉ZCuAl10Fe3,4种合金的耐磨性次序相应改变。     

硬质颗粒TiC对Al-Sn-Cu合金性能影响研究

采用光学显微镜(OM)、扫描电子显微镜(SEM)、能谱分析(EDS)以及硬度试验和摩擦磨损试验等方法,研究了TiC颗粒对Al-Sn-Cu合金组织、力学性能及摩擦磨损性能的影响,结果表明:添加TiC颗粒后该合金组织明显细化,平均晶粒尺寸由87μm降低至37μm,降幅达到57.4％;布氏硬度达到95.2 HB,比未添加Ti...     

钨对锌基合金ZA27力学性能的影响

与钛在ＺＡ２７合金中的作用相对比,分析了钨对锌基合金ＺＡ２７力学性能的影响。结果表明,钨可溶于ＺＡ２７合金组织中,产生一定的固溶强化作用;此外,钨在ＺＡ２７合金中可形成含钨化合物Ａｌ１５Ｚｎ５Ｗ,该经合物可作为初生α相结晶的核心,细化ＺＡ２７合金组强,大大改善合金的塑性。     

微量钇对铝-锌-镁-铜合金组织及力学性能的影响

为了提高铝-锌-镁-铜合金的力学性能,在合金中添加质量分数为0.15%的钇,并对其进行了均匀化和固溶时效处理;采用光学显微镜、X射线衍射仪和拉伸试验机等研究了添加微量钇对合金组织及力学性能的影响。结果表明:在合金中添加微量钇(0.15%)能明显细化合金的铸态组织和固溶态组织,使合金固溶时效后的抗拉强度提高4.7%,屈服强度提高5.5%;但由于添加钇导致了合金经均匀化处理后残留的共晶化合物增多,致使合金的伸长率下降了4.9%。     

锌对Mg-3%Al合金铸态显微组织和力学性能的影响

通过光学显微镜、万能力学试验机、X射线衍射仪和电子探针等分析了锌质量分数(1%~8%)对Mg-3%Al合金显微组织和力学性能的影响。结果表明:在Mg-3%Al合金中加入锌后对铸态显微组织和性能均有较大影响;锌质量分数为6%时,其主要组成相为-αMg基体相、-βMg17Al12相和-τMg32(Al,Zn)49三元相;合金的显微组织得到明显细化,各相分布也得到改善;此时其综合力学性能最好,抗拉强度、伸长率和断面收缩率分别达到了215 MPa,11.3%和11.2%。     

Minimal Realization of Linear Graph Models for Multi-physics Systems

An engineering system may consist of several different types of components,belonging to such physical"domains"as mechanical,electrical,fluid,and thermal.It is t...     

INTEGRAL EQUATION METHOD＇S APPLICATION IN HOLE-EDGE STRESS OF COMPOSITE MATERIAL PLATE WITH DIFFERENT SHAPED HOLES

The strength of composite plate with different hole-shapes is always one of the most important but complicated issues in the application of the composite material. The holes will lead to mutations and discontinuity to the structure. So the hole-edge stress concentration is always a serious phenomenon. And the phenomenon makes the structure strength decrease very quickly to form dangerous weak points. Most partial damage begins from these weak points. According to the complex variable functions theory, the accurate boundary condition of composite plate with different hole-shapes is founded by conformal mapping method to settle the boundary condition problem of complex hole-shapes. Composite plate with commonly hole-shapes in engineering is studied by several complex variable stress fimction. The boundary integral equations are founded based on exact boundary conditions. Then the exact hole-edge stress analytic solution of composite plate with rectangle holes and wing manholes is resolved. Both of offset axis loadings and its influences on the stress concentration coefficient of the hole-edge are discussed. And comparisons of different loads along various offset axis on the hole-edge stress distribution of orthotropic plate with rectangle hole or wing manhole are made. It can be concluded that hole-edge with continuous variable curvatures might help to decrease the stress concentration coefficient; and smaller angle of outer load and fiber can decrease the stress peak value.     

Non-monotonic material contrast in scanning ion and scanning electron images

30 keV Ga⁺ focused ion beam induced secondary electron (iSE) imaging was used to determine the relative contrast between several materials. The iSE signal compared from C, Si, Al, Ti, Cr, Ni, Cu, Mo, Ag, and W metal layers does not decrease with an increase in target atomic number Z₂, and shows a non-monotonic relationship between contrast and Z₂. The non-monotonic relationship is attributed to periodic fluctuations of the stopping power and sputter yield inherent to the ion–solid interactions. In addition, material contrast from electron-induced secondary electron (eSE) and backscattered electron (BSE) images using scanning electron microscopy (SEM) also shows non-monotonic contrast as a function of Z₂, following the periodic behavior of the stopping power for electron–solid interactions. A comparison of the iSE and eSE results shows similar relative contrast between the metal layers, and not complementary contrast as conventionally understood. These similarities in the contrast behavior can be attributed to similarities in the periodic and non-monotonic function defined by incident particle–solid interaction theory.     

Application of Feature Extraction through Convolution Neural Networks and SVM Classifier for Robust Grading of Apples

This paper proposes a novel grading method of apples,in an automated grading device that uses convolutional neural networks to extract the size,color,texture,an...     

分布动态载荷识别的抗噪处理

针对正交多项式频域法在用多种响应对矩形薄板进行载荷识别中抗噪性较差的问题,综合运用平均法、矩阵预处理和奇异值截断法等方法对之进行改善,并引入空间映射的思想,将该方法的应用范围拓展为复杂的模型.利用仿真算例,证实了该方法具有较好的抗噪性.     

Short-Term Relay Quality Prediction Algorithm Based on Long and Short-Term Memory

The fraction defective of semi-finished products is predicted to optimize the process of relay production lines, by which production quality and productivity ar...     

End-to-End Multiview Gesture Recognition for Autonomous Car Parking System

The use of hand gestures can be the most intuitive human-machine interaction medium.The early approaches for hand gesture recognition used device-based methods....     

基于MELTAC-N平台的核电厂安全级DCS环网研究与测试

针对工程实践中环网通讯相关问题的处理缺乏理论基础及国产化安全级DCS平台的开发缺乏成熟经验借鉴问题,对基于MELTAC-N平台核电厂安全级DCS环网的软硬件实现进行了研究。提出了安全级DCS环网双环网冗余设计、光切换开关设计等硬件设计方法,以及以RPR协议为基础,采用全数据收发策略的软件设计方法。在CPR1000安全级DCS平台上对安全级DCS环网的可靠性及实时性进行了评价,并进行了容错能力、响应时间及响应时间稳定性测试验证实验。结果表明,基于MELTAC-N平台安全级DCS环网软硬件设计具有较好的容错能力及响应时间稳定性。     

The laboratory simulation of abrasive wear

Abrasive wear has long been recognised as one of the most potentially serious tribological problems facing the operators of many types of plant and machinery; several industrial surveys have indicated that wear by abrasion can be responsible for more than 50% of unscheduled machine and plant stoppages. Locating the operating point of a tribological contact in an appropriate operational ‚map’︁ can provide a useful guide to the likely nature and origins of the surface degradation experienced in use, though care must be exercised in choosing the most suitable parameters for the axes of the plot. Laboratory testing of materials and simulations of machine contacts are carried out for a number of purposes; at one level for the very practical aims of ranking candidate materials or surface hardening treatments in order of their wear resistance, or in an attempt to predict wear lives under field conditions. More fundamentally, tests may be aimed at elucidating the essential physical mechanisms of surface damage and loss, with the longer term aim of building an analytical and predictive model of the wear process itself. In many cases, component surface damage is brought about by the ingress of hard, particulate matter into machine bearing or sealing clearances. These may be running dry although, more usually, a lubricant or service fluid is present at the interface. A number of standardised wear test geometries and procedures have been established for both two- and three-body wear situations, and these are briefly described. Although abrasive wear is often modelled as following an ‚Archard’︁ equation (i.e. a linear increase in material loss with both load and time, and an inverse dependence on specimen hardness) both industrial experience and laboratory tests of particularly lubricated contacts show that this is not always the case: increasing the hardness differential in an abrasively contaminated lubricated pair may not always reduce the rate of damage to the harder surface.     

ANGULAR DISTORTION ALLOWABLE VALUE AND ASSESS METHOD OF WELD ON COKE TOWER

A graph as the new engineering method for estimate the safety of bulging deformation of coke tower is proposed. Through stresses analysis of circumferential weld of coke tower and comparing the stresses produced by pressure with heat stress of steady state, residual stress, bending stress produced by both itself weight and wind loads, it showed that the stresses produced by pressure on the angle distortion are the main factor of equivalent stress of the combined stress. After comparing four kinds of stress controlling conditions, the relation to stress with depth of angular distortion, grade of curvature of angular distortion and half of region of angular distortion has been inferred. Graph of deformation allowable value of coke tower for different condition by angular distortion and half of region of angular distortion has been plotted. The five steps for its engineering use have been explained. The lighter the grade of curvature is, the larger of bulge allowance, may be, and the bigger of depth of angular distortion may pose too. For the coke tower with a popular structure of Dg 5 400 mm×28 mm, the result by graph is nearly more than the result of two formulas formed by other research, the error is less than 7.0%. But, the graph can be easily applied to different size of angular distortion.