电液锤上GH901合金涡轮盘模锻成形工艺

目的 研究GH901合金涡轮盘锻件的成形工艺.方法 采用有限元软件Simufact-2D对镍基高温合金涡轮盘的锤上模锻过程进行数值模拟分析,研究不同中间坯高径比下涡轮盘的填充效果及等效应变变化规律;研究不同锤击能量下涡轮盘的温度分布规律.结果 GH901合金涡轮盘锤上模锻时,中间坯高径比过大或过小均影响填充效果,同时不...     

GH4169合金研制进展

GH4169合金具有较高的高温强度,优异的持久、蠕变和疲劳性能,同时具备良好的加工和焊接性能,广泛用于航空、航天、石化等领域。随着航空、航天发动机性能的不断提高,对发动机关键用材GH4169在承温能力、持久蠕变性能和抗疲劳性能提出了更高要求,以满足先进航空发动机高性能、高可靠性、长寿命的需求。从合金改型、冶炼工艺优化、热加工技术提升等方面,系统论述了GH4169合金近50年基础研究成果及工程制备技术的进展。内容包括基于提高热稳定性,发展适应更高使用温度的改型合金的合金化原理;基于制备大尺寸、无偏析、纯净化铸锭的三联冶炼工艺技术进步;基于制备细晶棒材的快锻和径锻联合开坯的热加工技术提升;基于实现近净成形超塑性变形的热模锻和等温锻的最新进展。     

激光立体成形GH4169高温合金γ″相的高温粗化行为

采用激光立体成形技术制备GH4169高温合金块体,对其在720~780℃温度区间进行不同保温时间的双级时效处理,采用微观测试分析方法对高温短时时效处理后γ″相的形态、尺寸变化及粗化动力学行为进行研究。结果表明:激光立体成形GH4169合金在不同保温时间双级时效条件下,γ″相形态基本为圆盘形;和保温时间相比,时效温度对γ″相的影响更为显著;γ″相的粗化规律符合Lifshitz-Slyozov-Wagner(LSW)理论,计算获得γ″的粗化激活能Q=281.85kJ/mol,较锻造GH4169合金的γ″粗化激活能略高,表明激光立体成形GH4169合金的组织稳定性优于锻态。     

高温合金GH4169管材挤压工艺及组织分析

对高温合金GH4169管材挤压成形进行了工艺研究.确定了GH1140管材挤压成形工艺参数,分析了GH4169管材挤压力能参数变化规律.分析了管材挤压对组织性能的影响.研究结果发现,GH4169管材挤压成形时必须严格控制坯料温度、模具预热温度、润滑方式、挤压速度、挤压比等工艺参数.     

镍基高温合金微型涡轮盘热塑性成形工艺

目的 研究GH4698微型涡轮盘热塑性成形工艺。方法 采用有限元软件Deform-3D对镍基高温合金微型涡轮盘模锻过程进行数值模拟分析,研究坯料不同高径比、不同模锻温度下涡轮盘成形的最大载荷值、等效应力、等效应变、速度场的变化规律。结果 微型涡轮盘模锻过程载荷最大值随模锻温度升高而降低,温度和高径比对涡轮盘的凸台、直榫等部位的等效应力、等效应变影响有明显的差异。在涡轮盘路径1上,随着温度的升高,等效应力逐渐降低,变形更加均匀;随着高径比的增加,变形不均匀程度增大,高径比为1时等效应力的极大值最小;温度和高径比对速度场的影响较小。结论 温度和高径比对GH4698微型涡轮盘锻造变形行为有显著的影响,选择合适的模锻工艺参数可以有效降低成形载荷,并获得使用性能较好的微型涡轮盘。     

强韧化GH4169合金盘件锤锻累积形变与锻件温升的热功分析

本文进行了Gh4169合金盘件的锤锻试验。结果表明,在930～1010℃范围内,单锤变形量δ_0为2.0～4.0％时,两火次累积变形量大于60％的锤锻变形工艺,可获得ASTM9～10级的均匀细晶锻件组织。     

锻态GH4169合金热变形本构方程及热加工图

目的 研究锻态GH4169合金的热变形行为,获得优化的热加工参数。方法 采用Gleeble 3500热模拟实验机对锻态GH4169合金进行不同工艺参数的热压缩实验,建立锻态GH4169合金的热变形本构方程,分析流变应力与热加工参数之间的关系。根据获得的流变应力–应变曲线建立锻态GH4169合金的热加工图。采用金相显微镜观察锻态GH4169合金变形后的显微组织。结果 锻态GH4169合金的应力随变形温度的增加和应变速率的降低而降低。基于锻态GH4169合金的热加工图可知,锻态GH4169合金可热加工的区域分别为987～1 027℃/0.026～0.01 s^-1和1 070～1 100℃/0.026～0.01 s^-1,最优热加工参数分别为1 000℃/0.01 s^-1和1100℃/0.01s^-1。通过金相组织结果分析可知,锻态GH4169合金无论在低温高应变速率条件下,还是在高温低应变速率条件下都发生了再结晶。对于热加工图中的流变失稳区,合金的动态再结晶主要与变形热有关。对于热加工图中可热加工的区域,合...     

GH4169合金锻造混晶组织的均匀细化机制与工艺

目的 消除GH4169合金锻造混晶组织,获得高品质GH4169合金锻件的制备工艺.方法 对变形后锻件进行后续的热处理退火,探明均匀细化锻造混晶组织的热处理工艺方法与机制.首先,设计并实施不同的单级退火工艺及双级退火工艺.随后,统计不同热处理退火工艺下锻造混晶组织的平均晶粒尺寸.最后,分析不同热处理退火工艺下混晶组织的细...     

GH4169集合器超塑成形有限元分析及预成形研究

为了成功超塑成形GH4169高温合金集合器并降低研制成本,采用有限元分析对GH4169合金集合器超塑成形过程进行了数值模拟,并采用拉深成形工艺对集合器超塑成形所需的预成形进行了研究.结果表明:超塑成形需筒形预成形件,且聚料工步是超塑成形出满足设计要求的零件所必需的一道工序;成功地拉深出集合器超塑成形预成形件;合金经预拉深成形后,在超塑成形温度(950℃)下保温30 min后仍是ASTM 10级以上的细晶组织,能够满足超塑成形所需的细晶组织的要求.     

隧道掘进机滚刀刀圈模锻成形工艺的模拟与实验研究

目的 提出锤上模锻的成形工艺,进行滚刀刀圈的制造,以改善和提高隧道掘进机（Tunnel Boring Machine,TBM）滚刀刀圈的模锻成形质量。方法 基于TMB滚刀刀圈的结构及特征,制定滚刀刀圈的模锻成形工艺,建立锤上模锻和液压机模锻成形的数值模拟模型,通过数值模拟分析对比2种工艺下滚刀刀圈的成形质量和温度场、模具应力等各场变量。基于数值模拟结果,采用锤上模锻的工艺进行刀圈成形实验研究,对比分析实验和数值模拟过程中的打击次数、锻件外观及尺寸、截面流线、飞边长度等特征。结果 数值模拟结果表明,采用液压机模锻成形的刀圈内部及刃部流线易出现折叠缺陷,模锻结束后锻件温降严重且模具应力较大;而采用锤上模锻成形的刀圈刃部流线分布合理,内部成形均匀性较好,模锻结束后锻件温度为992～1 170℃,成形模具应力为1 348 MPa,小于液压机模锻的模具应力,满足模具强度要求。锤上模锻成形实验结果表明,成形实验和数值模拟的打击次数较为吻合,成形外观一致,刀圈截面流线分布相似,没有明显的尺寸误差和飞边长度误差。结论 采用锤上模锻成形工艺成形滚刀刀圈具有较高的工艺可行性和较好的成形质量。     

凝固科学技术与材料

从凝固科学与实践发展的角度介绍了当前凝固材料体系的基本框架和凝固科学主要发展阶段的基本理论。作为材料科学与工程的基本组成，凝固科学技术正在现代科学理论的基础上针对传统材料的改性提高和新材料的发展需求，以控形、控构、控性为目标开展优质铸件的定向、晶体生长、快凝、深过冷及各种新型和超常领域凝固过程的研究，并介绍了其中某些方面和展望了可能的发展趋势。     

Development and challenges of planning and scheduling for petroleum and petrochemical production

Production planning and scheduling are becoming the core of production management, which support the decision of a petrochemical company. The optimization of production planning and scheduling is attempted by every refinery because it gains additional profit and stabilizes the daily production. The optimization problem considered in industry and academic research is of different levels of realism and complexity, thus increasing the gap. Operation research with mathematical programming is a conventional approach used to address the planning and scheduling problem. Additionally, modeling the processes, objectives, and constraints and developing the optimization algorithms are significant for industry and research. This paper introduces the perspective of production planning and scheduling from the development viewpoint.     

江澳两地高校文创设计的协同研究与商业实践

目的 探索江门世遗文化的传承、发展和转化的新思路,践行国家在《粤港澳大湾区发展规划》纲要中要求江门承担与港澳地区文化创意合作与开发任务的分工。方法 与澳门高校紧密合作,开展专业培训课程,以开平碉楼为例,从人文视角开展设计研究,梳理开平碉楼的文化脉络,把世遗文化的元素和其背后的文化融入文创产品中,提升文创产品的附加值,推动当地文创产业结构的变革。结果 两地高校构建了稳定的科研团队,开设长期有效的设计培训课程,与景区建立了研究协作关系,帮助景区构建了一套产销研的商业模式。结论 以跨区域高校合作为平台,以文创产品为抓手,依托江澳两地的资源优势,可以构建江门世遗文化全新的品牌形象,最终推动开平世遗文化的活化。     

Error and uncertainty in modeling and simulation

This article develops a general framework for identifying error and uncertainty in computational simulations that deal with the numerical solution of a set of partial differential equations (PDEs). A comprehensive, new view of the general phases of modeling and simulation is proposed, consisting of the following phases: conceptual modeling of the physical system, mathematical modeling of the conceptual model, discretization and algorithm selection for the mathematical model, computer programming of the discrete model, numerical solution of the computer program model, and representation of the numerical solution. Our view incorporates the modeling and simulation phases that are recognized in the systems engineering and operations research communities, but it adds phases that are specific to the numerical solution of PDEs. In each of these phases, general sources of uncertainty, both aleatory and epistemic, and error are identified. Our general framework is applicable to any numerical discretization procedure for solving ODEs or PDEs. To demonstrate this framework, we describe a system-level example: the flight of an unguided, rocket-boosted, aircraft-launched missile. This example is discussed in detail at each of the six phases of modeling and simulation. Two alternative models of the flight dynamics are considered, along with aleatory uncertainty of the initial mass of the missile and epistemic uncertainty in the thrust of the rocket motor. We also investigate the interaction of modeling uncertainties and numerical integration error in the solution of the ordinary differential equations for the flight dynamics.     

Density and viscosity of tetralin and trans-decalin

New measurements are reported for the density and viscosity of tetralin and trans-decalin. The density was determined from room temperature to 60°C for tetralin and to 95°C for trans-decalin. The kinematic viscosity was measured up to temperatures slightly above 100°C. Our results improve upon the values recommended by the American Petroleum Institute for these liquids.     

The Candela and Photometric and Radiometric Measurements

The national measurement system for photometric and radiometric quantities is presently based upon techniques that make these quantities traceable to a high-accuracy cryogenic radiometer. The redefinition of the candela in 1979 provided the opportunity for national measurement laboratories to base their photometric measurements on optical detector technology rather than on the emission from high-temperature blackbody optical sources. The ensuing technical developments of the past 20 years, including the significant improvements in cryogenic radiometer performance, have provided the opportunity to place the fundamental maintenance of photometric quantities upon absolute detector based technology as was allowed by the 1979 redefinition. Additionally, the development of improved photodetectors has had a significant impact on the methodology in most of the radiometric measurement areas. This paper will review the status of the NIST implementation of the technical changes mandated by the 1979 redefinition of the candela and its effect upon the maintenance and dissemination of optical radiation measurements.     

Creation and motion of dislocations and fracture in metal and silicon crystals

By making a step on one surface ( ) of a rectangular small paralellepiped copper crystal, dislocations could be created by the molecular dynamic method. The dislocation created was not a complete edge dislocation but a pair of Heidenreich-Shockley partial dislocations. Each time a dislocation was created, the stress on the surface was released. Small copper crystals having a notch were pulled (until fracture), compressed and buckled by use of the molecular dynamic method. An embedded atom potential was used to represent the interaction between atoms. Dislocations were created near the tip of the notch. A very sharp yield stress was observed. The results of high speed deformations of pure silicon small crystals using the molecular dynamics are presented. The results suggest that plastic deformation may be possible for the silicon with a high speed deformation even at room temperature. Another small size single crystal, the same size and the same surfaces, was compressed using molecular dynamic method. The surfaces are {110}, {112} and {111}. The compressed direction was [111]. It was found that silicon crystals are possible to be compressed with a high speed deformation. This may suggest that silicon may be plastically deformed with high speed deformation.     

SMC／BMC的回收与再利用

SMC／BMC废弃物对工业及环境造成了很大影响，指出了SMC／BMC回收再利用的紧迫性。通过对目前国际上SMC／BMC回收再利用的3种典型途径优缺点的对比，参照国外SMC／BMC回收再利用的先进方法，对我国SMC／BMC回收再利用提供了可行的建议．