影响Cu-Ni-Si合金时效效果的因素分析

对Cu-3．2Ni-0．75Si-0．3Zn合金的时效工艺进行了正交试验，结果发现，各因素对合金导电率和显微硬度影响程度的主次顺序为：时效温度〉合金状态〉时效时间。综合分析后认为，该舍金热轧板材经60％冷变形后，可直接时效而省去固溶处理。析出相的体积分数、颗粒半径、颗粒间距分别是该合金时效初期、中期和后期影响强化效果的主要因素，因而在时效过程中该合金分别遵循3个不同的强化规律。     

热处理工艺对铜-锌-铬合金硬度的影响

通过对不同热轧态的Cu-17.0Zn-0.4Cr合金在不同热处理状态下的硬度测定和显微组织观察,分析了热处理工艺对合金硬度的影响.结果表明:随着时效时间的延长和时效温度的增加,合金的硬度下降;0～525 ℃)×1 h时效,硬度可达110 HV以上.     

GH4169合金细晶成形工艺与机理及其性能研究

用热机械加工和光学与扫描电镜观察的方法 ,对GH4 16 9合金板材的δ相析出规律及其超细化工艺进行了研究。结果表明 :对GH4 16 9合金板材进行 890℃× 10h处理 ,可以析出足够数量的针状δ相 ,该相具有良好的热稳定性 ;对该板材采用 10 5 0℃× 0 .5h + 5 0 %冷轧变形 + 890℃× 10h + 2 0 %～ 30 %冷轧变形 + 95 0℃× 3h的工艺后 ,可以得到ASTM 12～ 14级的超细晶粒组织 ;所获得的超细晶合金与普通合金相比 ,其 6 5 0℃高温抗拉强度及伸长率均有所提高     

时效处理对热轧铜-锌-铬合金导电性能的影响

研究了不同时效工艺对热轧铜-锌-铬合金导电性能的影响,并对最优工艺处理后合金的组织及相组成进行了分析.结果表明:试验条件下,Cu-17Zn-0.4Cr合金的最佳生产工艺为930℃热轧后淬火 550℃×1 h时效,合金的电导率为55.1%IACS;热轧温度一定时,随着时效温度升高,电导率先增大后减小,存在电导率最大值;热处理工艺一定时,则热轧温度越高,电导率越低.     

时效工艺对Cu-1.9Be-0.25Co合金析出行为的影响

对Cu-1.9Be-0.25Co合金进行780℃×4 h固溶处理与不同温度(300,320,340,360℃)和不同时间(1,2,4,8,16 h)的时效处理,研究了时效工艺对合金析出行为的影响规律.结果表明:获得峰时效的时效工艺为320℃×8 h,此时合金的硬度为422 HV;在320℃时效过程中合金析出相的演变规律为亚稳γ″相→半共格γ'相→非共格γ平衡相;时效初期(1～2 h)析出相短时间内大量析出是合金硬度快速升高的主要原因,时效中期(2～8 h)析出相与铜基体的半共格关系是获得峰时效的主要原因,时效后期(8～16 h)析出相和基体脱离半共格关系,合金发生过时效,硬度降低.     

稀土Y对Cu—0．35Al合金薄板带内氧化动力学的影响

对Cu-0．35Al-Y合金薄板带在短时间内的内氧化动力学进行了试验研究,测定了合金内氧化层的显微硬度和导电率。结果表明,Cu-0．35Al—Y合金薄板带在0．5h到2h进行内氧化,其内氧化动力学曲线呈抛物线变化;微量稀土元素Y的加入促进了Cu-0．35Al合金薄板带的内氧化;随着内-氧化时间的延长,合金的内氧化层深增加;本试验条件下,经950℃、2h内氧化,Cu-0．35Al—0．05Y合金薄板带试样内氧化层深达355μm,内氧化层显微硬度为101．5HV,导电率为82．5%IACS。     

CuNiBeSiRE合金强化工艺研究

研究了固溶、时效及冷变形后时效等工艺对CuNiBeSiRE合金组织和性能的影响。研究表明，该合金经930℃固溶1．5h 30％冷变形 490℃时效3h炉冷处理，具有高的强度、导电率和软化温度，且其物理性能和力学性能达到较佳的配合，达到了原定技术指标，满足了服役条件苛刻的汽轮发电机组转子槽楔的使用要求。     

7005铝合金热处理工艺研究

通过力学性能以及抗应力腐蚀的测定,对7005铝合金的热处理工艺进行了研究。结果表明,该合金较为理想的热处理制度是470℃固溶处理后水淬,人工时效制度为双级时效100℃×8 h+120℃×24 h。热处理后,合金的室温拉伸强度达到400 MPa以上,抗腐蚀性能良好,析出相呈细小而弥散分布,对合金有很好的强化效果。     

Cu-15Ni-8Sn-0.4Si合金时效过程研究

用相对电导率、硬度的测量、金相分析及透射电镜等方法，研究了Cu-15Ni-8Sn-0．48i合金在380℃时效过程中组织结构及性能的变化。结果表明，时效过程中，细小Ni2Si颗粒的析出对不连续沉淀有一定抑制作用；随时效时间增加，抑制作用减弱；Cu-15Ni-8Sn-0．4Si合金的电导率、硬度比Cu-15Ni-8Sn合金高。     

铜镍硅锌镁合金的时效析出动力学

分析了时效温度(400~550℃)和时效时间(0~8h)对铜镍硅锌镁合金导电率的影响,推导了导电率和新相析出率之间的关系,在此基础上,根据Avrami相变动力学经验方程推导出了试验合金在400~550℃时效时的相变动力学方程和导电率方程,并计算出该合金在不同温度下时效时的相变开始和结束时间。结果表明:在时效初期,试验合金的导电率迅速上升,之后趋于平缓;温度越高,时效相同时间后的导电率越高;导电率和新相析出率之间存在线性关系,可以用导电率的变化来间接反映相变过程;根据导电率方程计算得到的导电率与试验结果吻合;试验合金在500℃时效时的相变开始时间和结束时间最短,分别为0.34,7 083.23s。     

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.     

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。     

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....     

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.