美国FORGE计划犹他州干热岩开发示范项目进展综述

21世纪是全球能源获取方式发生重要变化的时代。现有以煤炭、石油、天然气等传统资源为基础的能源正在逐渐被风能、太阳能、生物质能、地热能等环境友好、低排放的绿色能源所取代。干热岩是一种不含原生水(或含少量水但不能流动)的高温地热资源,可通过水力刺激改造形成增强型地热系统储层,从而提取数量相当可观的地热能。本文以美国能源部正在组织实施的FORGE计划犹他州干热岩示范项目为研究对象,综述了项目在场地地质条件表征、基础设施建设等方面取得的主要进展与成果,总结了项目在高温硬岩钻井、储层建造、微震监测等方面取得的广泛且深入认识,从统筹部署、组织实施、场地表征和设施建设、关键技术装备突破、数据共享等方面提出了值得我国借鉴参考的具体实践。

Effect of forging on the microstructure and texture of a high Nb containing γ-TiAl alloy

The effect of forging on the microstructure and texture evolution of a high Nb containing Ti-45Al-7Nb-0.3W(at.%)alloy was investigated by X-ray diffractometer(XRD),scanning electron microscopy(SEM),and transmission electron microscopy(TEM).The results show that the as-cast alloy is mainly composed of α_(2)/γ lamellar colonies with a mean size of 70μm,but the hot-forged pancake displays a near duplex microstructure(DP).Kinking and bending of lamellar colonies,deformation twinning and dynamic recrystallization(DRX)occur during hot forging.Meanwhile,dense dislocations in theβphase after forging suggest that the high-temperature β phase with a disordered structure is favorable for improving the hot-workability of the alloy.Unlike the common TiAl casting texture,the solidification process of the investigated as-cast alloy with high Nb content is completely via the β phase region,resulting in the formation of a<110>γ fiber texture where the<110>γ aligns parallel to the heat-flow direction.In comparison,the relatively strong<001>and weak<302>texture components in the as-forged alloy are attributed to the deformation twinning.After annealing,static recrystallization occurs at the twin boundary and intersections,which weakens the deformation texture.

Simulation-Based Investigation of Crack Formation in Forged MB15 Magnesium Alloy

In the process of riveting an MB15 forging die,cracks were discovered emerging along the longitudinal direction and near the riveting hole.Through fracture analysis,microscopic observation,energy spectrum analysis,metallographic examination,and hardness test,the properties and causes of the cracks are discussed.The results indicate that the cracking type is intergranular brittle cracking,occurring during the forging stage.Furthermore,the recrystallization at the crack site is found to be incomplete,which is attributed to the low deformation temperature.

基于Forge的KD锻造法自动化仿真

根据KD锻造法的工艺特点,将KD锻造法工序分解成布砧、压下、翻转、进给四个工步,并循环往复。在此基础上,通过Forge有限元模拟软件匹配KD锻造法工艺参数,分析变形过程中关键指标的动态变化,验证KD锻造法自动化生产的合理性和可行性,为轴类锻件自动化生产提供数据支撑。

Microstructures and mechanical properties of 2014 aluminium alloy forgings made by a new process

The triangular 2014 aluminium alloy forgings were made by a new process and the traditional process. The results showed that the mechanical properties of the forgings made by the new process are far higher than that in the standard of GB223 84, and also higher than that in the standard of EL/53MI 94; moreover, the mechanical properties are almost the same in each direction, and anisotropies are very small. The grains and 2nd phases were analyzed by using TEM and SEM, the results indicate that very fine grains (3～6 μm)appear in an approximately isometric way, and a large number of 2nd submicrophases(0.05～0.15 μm) disappear in no apparently preferred orientation distribution because the new process involves multidirectional heavy plastic deformation (λ=12), solution(500 ℃/400 min) and ageing(165 ℃/10 h) heat treatments for a long time at high temperatures. These refined grains, 2nd submicrophases and their almost homogeneous distribution can make it possible for the forgings to display high mechanical properties.

Manufacturing of ultra-large plate forgings by unfolding and flattening of thick cylinders

Ultra-large plate forgings are foundation of heavy machinery,but many parts of the type cannot be made by conventional technologies due to the characters of extreme manufacturing in terms of size and quality requirements.This paper introduced a systematically method called cylinder unfolding method(CUM)for producing large plate forgings,by using a serial of operations including“splitting”,“unfolding”,and“flattening”of a thick cylinder obtained from saddle forging.The technological route of CUM was presented in detail with an example of plate forging with the horizontal sizes of 6100 mm and thickness of 300 mm.The deformation features of saddle forging for fabricating transitional cylinders were analyzed,and then the subsequent handling steps including splitting,unfolding and flattening of the cylinder,as well as the auxiliary processing,were addressed.The practice proved that CUM can provide an efficient way for manufacturing ultra-large plate forgings and meet the strict requirements in geometry and mechanical performance,without highly increasing the investments of forming equipment and tooling.

STUDY ON THE FORMATION OF DEFECTS IN DURALUMIN FORGINGS

The mechanism of forming defects in 2024. 7075 series aluminium alloy forgings has been studiedby means of metallography. EDAX. SEM etc. The defects are divided into two types by their appearance.needle-shaped and flake-shaped. The mechanism of them forming is discussed. It has been testified that thedefects result from hydrogen or oxide film. The defects can be prevented by controlling the hydrogen contentin the melt and keeping oxide film from involving.

Effect of heat treatment on the microstructure and mechanical properties of a multidirectionally forged Mg-Gd-Y-Zn-Zr-Ag alloy

Multidirectional forging(MDF)was successfully applied to fabricate large-size Mg-Gd-Y-Zn-Zr-Ag alloy in this work and effects of T4,T5 and T6 treatments on the microstructure and mechanical properties of the as-forged alloy were analyzed.Results show that dynamic recrystallization(DRX)occurs and second phase particles precipitate along the grain boundary during the MDF process.After annealing treatment(T4),the volume fraction and size of dynamic precipitates slightly increase at a lower temperature(430℃)compared with those of MDFed sample,while they are dissolved into theα-Mg matrix at a higher temperature(450℃).At the meantime,short plate-shaped long-period stacking ordered(LPSO)phases are observed in the DRX grains of the MDFed sample and then dissolved into theα-Mg matrix during annealing at both temperatures.Typical basal texture is identified in the MDFed sample,but the basal pole tilts away from final forging direction and rare-earth texture component with<1121>orientation parallel to penultimate forging direction becomes visible after annealing.The T6 sample annealing at 430℃for 4 h and ageing at 200℃for 34 h exhibits the superior strength and ductility in this study.The ultimate tensile strength,tensile yield strength and elongation to failure,which is 455 MPa,308 MPa and 7.7%,respectively,are overall improved compared with the directly-aged(T5)sample.This paper provides a superior heat treatment schedule to manufacture high-performance large-scale Mg-Gd-Y-Zn-Zr-Ag components for industrial production.

MICROSTRUCTURAL EVOLUTION AND CONTROL IN SUPERALLOY FORGINGS

Optimum properties of high temperature superalloys are derived from interactions of the composition,thermomechanical deformation, and heat treatment.Nickel-base alloys contain a variety of alloying elements in a large number of combinations to produce various desired effects. The general characteristics of any specific nickelbase superalloy is determined by composition.The control of the microstructure in wrought processed superalloys can further influence the resultant component properties.The relationship between microstructure and properties is key in advanced design and manufacture of turbine engine components, and requires extensive alloy and process characterization to achieve desired results.Various forging methods have been developed and employed throughout the years to process superalloy components.Hammer forging, Press forging,and advanced isothermal press forging equipment and processes have been designed and manufactured to process speciality metals which often have very narrow processing windows.Combination processes have also been introduced into turbine engine applications,which result in a hybrid of resultant structures and properties.One such speciality,combination process is the Ladish Iso Con process which utilizes isothermal forging and conventional forging to achieve unique properties not matched by any other single process.Ladish utilizes forging presses for conventional forging, hot-die forging and for isothermal forging, in addition to hammers and ring rolling mills for wrought processing.This wide range of equipment allows flexibility in process design and optimization.Variations in temperature, strain and strain rate have been shown to significantly influence resultant grain sizes and microstructures.Tools are being developed to allow forging processes and specific forging parameters to be evaluated and optimized with regard to final microstructure before shop triale are required. Sophisticated finite element method (FEM) models are allowing the design of forging processes on computers rather than by iterative trial and error methods.

Effect of nitrogen content on the microstructure and mechanical properties of titanium-bearing nonquenched and tempered steel after hot forging

The microstructure and mechanical properties of titanium(Ti)-bearing medium-carbon nonquenched and tempered steel with different nitrogen content before and after hot forging were investigated through smelting,forging,and laboratory tests.The results show that the grain size of nonquenched and tempered steel was gradually refined,and the ferrite content gradually increased with an increase in nitrogen content.The grain size of the material with low nitrogen content increased abnormally,and its impact properties significantly decreased after hot forging.The grain size of nonquenched and tempered steel with higher nitrogen content was slightly larger than that before forging,and the tensile and yield strength increased,but the impact toughness was not significantly reduced.The Ti-bearing nonquenched and tempered steel showed better strength and toughness after hot forging with the addition of 0.010%0.015%nitrogen.

大党独有难题的认知逻辑与破解之道

时刻保持解决大党独有难题的清醒和坚定,中国共产党方能行稳致远。党以整体规模大、历史跨度大、志向抱负大等显著性特征展现“大的样子”,大党基于应有的“大的担当”肩负党内治理、国家治理、社会治理等治理任务。中国共产党作为大党,要实现高效能治党治国,必须从思想理念、政治整合、能力提升、精神状态、防错纠错、生态营造等方面剖析面临的独有难题,并给出有针对性的治理路径。大党独有难题的终极破解之道,依赖“大党之能”,借助能力涵养从领导权威、思想指南、本领本事、斗争精神、自我革命、人民支持上形成一揽子行动方略。

基于混晶评价的大锻件热锻晶粒组织演变

以大型锻件超超临界转子用12%Cr耐热钢为研究对象,采用拔长实验和数值模拟相结合的方式,探究了大锻件热锻过程晶粒组织演变情况。研究表明:热锻后坯料横截面晶粒不均匀性受锻造温度、锻比以及上模压下速度综合影响,小锻比和较低锻造温度与大锻比和较高锻造温度均可改善晶粒不均匀性。基于此,通过拟合得到了12%Cr耐热钢热锻过程坯料横截面晶粒不均匀性与锻造工艺参数之间的量化关系模型;针对大锻件“因大而生”的混晶问题,在现有混晶评价方法的基础上,提出了一种普适性更好的混晶评价方法,即采用统计学方法划分各小组,以每小组晶粒弦长和占总弦长的频率为基础,分别确定大、小晶粒分界组进行评价,对比拔长实验后的混晶组织演变规律验证了该方法的优越性。

以铸牢中华民族共同体意识涵化民族村寨旅游的发展机理与实践进路

中华民族共同体意识是民族团结之本。支持特色村寨的保护与发展是我国民族工作的重要组成部分。民族村寨在推进旅游发展过程中,要牢牢把握铸牢中华民族共同体意识这条主线,深入开展民族团结进步创建工作,实现以铸牢中华民族共同体意识为主线贯穿民族村寨旅游内涵式发展,以民族村寨旅游发展助力铸牢中华民族共同体意识良性互动的发展机理。同时,涵化民族村寨旅游发展必须以乡村文化展馆“塑形”,以智慧民族村寨“赋能”,以文旅融合发展“做实”,以民族村寨文化“铸魂”,以乡村三治融合“协治”,以文塑旅,以旅彰文,推动铸牢中华民族共同体意识在民族村寨旅游内涵式发展中实现“纲举目张”。

近净成形快堆支承环用316H不锈钢锻件的晶粒度与力学性能

采用电渣重熔钢锭,经开坯锻造后,通过热挤压制备高品质坯料,随后在专用模具内进行胎模锻造成形,研制出国内首支外径15.5米、重量15吨的快堆支撑环1/6弧段316H不锈钢锻件,突破了超大规格快堆支撑环锻件制造技术瓶颈。结果表明:锻件各部位晶粒度、拉伸性能均匀一致且无各向异性,疲劳性能完全满足ASME设计曲线标准要求。所采用的近净成形制造工艺大大缩短了产品制造周期,提高了经济效益,实现了同类产品的国产化制造。

双机镜像搅拌摩擦焊顶锻力变化规律与影响因素研究

随着搅拌摩擦焊板厚增大,设备承载能力无法满足单侧搅拌摩擦焊的高顶锻力要求,因而难以形成质量良好的焊缝。为了降低设备所受顶锻力,本文提出了一种双机镜像搅拌摩擦焊工艺方法,研究了工艺过程中顶锻力的变化规律和影响因素,并验证了该工艺的可行性和优越性。首先,建立热力耦合的有限元仿真模型,得到顶锻力随板厚的变化规律,同时得到了双机镜像搅拌摩擦焊工艺能够减小顶锻力的结论;之后,建立顶锻力估计模型,并基于数据驱动对模型进行试验修正和验证,实现无传感器的顶锻力监测;最后,在搭建好的试验平台样机上开展了镜像焊接试验、3组工艺参数的多因素试验及单侧搅拌摩擦焊对比试验,得到顶锻力随时间的变化规律和工艺参数的影响,验证了双机镜像搅拌摩擦焊工艺可以减小搅拌头所受顶锻力、降低设备承载能力需求的作用。

限制型多向锻造对Ti_(2)AlNb基合金组织与性能的影响

在B2+O相区下对Ti_(2)AlNb基合金进行三道次等温限制型多向锻造(R-MDF),借助金相显微镜、X射线衍射仪、扫描电子显微镜和透射电子显微镜对变形后的合金试样组织进行分析,通过Image软件定量统计多向锻造各道次O相的总体积分数、板条O相的宽度和体积分数以及等轴O相的尺寸,研究不同道次下O相的变形行为;对不同道次下Ti_(2)AlNb基合金试样进行维氏硬度测试,揭示Ti_(2)AlNb基合金经多向锻造后微观组织与显微硬度之间的关系。研究结果表明:变形结束后,粗大的板条O相破碎细化成等轴O相;经不同道次的多向锻造后,等轴O相尺寸先由一道次的0.57μm增大到二道次的1.24μm后又逐渐细化,三道次后平均尺寸为0.84μm左右;相较于初始试样,各道次试样显微硬度分别提升约15.4%、22.2%和14.8%。

重卡传动轴用高强7075铝合金热流变行为及径向锻造微观组织演变

为研究重型卡车轻量化传动轴用高强7075铝合金在径向锻造时的热变形行为,将大直径7075铝合金挤压棒料预热退火后,取样进行了不同变形条件下的等温压缩试验。分别考虑温度与应变速率对应变强化及软化的影响,构建了适用于中大型7075铝合金传动轴热加工的改进Hansel-Spittel本构模型。根据动态材料模型理论获得了7075铝合金的热加工图,并据此分析了7075铝合金棒料在典型径向锻造工艺中的组织变化。研究结果表明:改进Hansel-Spittel模型能更准确地模拟预热退火态7075铝合金的峰值和稳态流变应力,预测值与试验值的平均相对误差仅为2.71%;7075铝合金在温度为350~450℃、应变速率为0.01~10 s^(-1)范围内具有较高的热加工稳定性,高温及低应变速率的变形条件有利于材料的微观组织演化;预热退火态7075铝合金棒料在经过截面收缩率为55.6%的径向锻造工艺和T6热处理后,原始板条晶粒转变为细化大转角晶粒组织,抗拉强度提高至651 MPa,延伸率提高至12.5%,综合性能得到显著改善。

铸牢中华民族共同体意识融入民族地区语言教育对策研究

民族地区语言教育发展是推动各族群众交往交流交融,促进民族团结的重要举措。民族地区只有不断加强国家通用语言文字教育才能更好地适应当前阶段的客观需要,加强民族间的交往交流交融,实现书同文、语同音、心相通、情相融。文章基于民族地区通用语言教育对于铸牢中华民族共同体意识的重要意义,通过梳理既有文献及研究成果,了解当前民族语言教育发展现状,就部分民族地区语言教育存在的突出问题,提出了加强语言教育师资队伍、加大语言教育投入力度、推广普及国家通用语言文字、增强课程思政在语言教育课堂的融合程度四条策略,并认为在民族地区推广普及国家通用语言文字,要开拓创新,多措并举,多管齐下,切实解决当前存在的问题,加快推进民族地区语言教育进程,以语言相通促进各族群众的沟通交流和国家认同,进而铸牢中华民族共同体意识。