Nickel-based powder metallurgy superalloys with high W and high gamma ' content exhibit excellent high-temperature properties, but their high deformation resistance poses significant challenges for hot processing. In this study, the hot compression behaviour of an extruded nickel-based powder superalloy FGH4109 with high W (6.1%) and high gamma ' phase contents (60%) was systematically investigated at temperatures ranging from 1060 degrees C similar to 1140 degrees C, strain rates from 0.001 s(-1) similar to 1 s(-1), and maximum true strains of 0.7. Combined with the hot working map and the microstructure evolution in different hot working zones, the optimal hot working window for the alloy was determined to be in the temperature range of 1060 degrees C similar to 1140 degrees C and strain rates of 0.001 s(-1) similar to 0.012 s(-1), where the power dissipation efficiency eta was greater than 0.5, and the dominant deformation mechanism was discontinuous dynamic recrystallisation.

The creep behavior of a novel powder metallurgy (PM) Ni‐based superalloy is investigated at temperatures ranging from 760 to 815 °C and stress levels in the 480–620 MPa. The steady‐state creep rate, strain to rupture, and rupture time are analyzed based on the Monkman–Grant relation (MGR) and the modified MGR (MMGR). The creep damage factor is redefined by the analysis of Monkman–Grant ductility (MGD). A general relationship between the time reaching MGD and creep life is established. The sharply accelerated creep stage is proposed and the MMGR of the transient creep parameters in this stage is established. The nucleation, growth, and connection of grain‐boundary creep cavities dominate the creep damage of the alloy. The stress concentration caused by the accumulation of dislocations at grain boundaries and σ‐phase interfaces and the grain‐boundary slipping are the main reasons for the nucleation of grain‐boundary cavities. The coupling effect of the temperature and the stress aggravates the damage of grain boundary and the degradation of microstructure.

Nickel-based powder metallurgy（PM）superalloy FGH4107 with five varied Zr contents were prepared by the high-throughput preparation,including vacuum induction melting（VIM）,electrode induction-melting gas atomization（EIGA）,and hot isostatic pressing（as-HIPed）processes.The effects of Zr content（mass fraction 0～0.50%）on the equilibrium phases thermodynamics,kinetic behavior and γ/γ′lattice misfit degree were studied by the calculation and simulation of JMatPro 6.5 software,combined with differential scanning calorimetry（DSC）and X-ray diffraction（XRD）.The results show that in the range of 600-1 400℃,the Zr content has little effect on the types of equilibrium phases,which are mainly composed of L,γ,MC,MB 2 ,γ′,M 3 B 2 ,M 23 C 6 ,μandσphases,Zr atoms enter γ,γ′,MC and Ni 7 Zr 2 phase in turn.With the increasing of Zr content from 0 to 0.50%,the initial melting temperature is greatly reduced but the final melting temperature is slightly decreased,and the temperature range of the solid-liquid two-phase region is enlarged.However,the Zr content has little effect on the solvus temperature of the γ′phase.With the addition of Zr from 0 to 0.50%,γ′/γ lattice misfit degree increases from 0.215%to 0.265%,indicating that Zr enters γ′phase and enhances the precipitation strengthening effect.

库车大峡谷位于新疆维吾尔自治区阿克苏地区的库车县北部,是天山支脉克孜利亚山中的一条峡谷,也被称为"天山大峡谷".因其崖壁陡峭、颜色赤红,当地维吾尔人将其称为"克孜利亚",意为"红色的山崖".库车大峡谷位于库车县城北部约70公里处,不仅是国家地质公园,还是"全国十大最美峡谷"之一,是丝绸之路北道与国道217线(独库公路)中段新疆"黄金旅游走廊"上的一颗璀璨明珠(见图1、图2).

To further develop Ni-based PM superalloys for aero-engines, it is critical to understand their deformation mechanisms at various service temperatures. For turbine disks, tensile strength and plasticity are critical indexes. The high strain rate in tensile deformation makes it essentially different from creep. In this paper, a high-performance PM superalloy with various Ta was evaluated by tensile tests at different temperatures from room temperature to 815 °C. The relationship between temperatures and plastic deformation mechanisms was explored from multiple scales using scanning electron microscopy and transmission electron microscopy. Whereafter, temperature dependence of deformation mechanism map was established. The results demonstrated that the main deformation mechanism gradually changes from antiphase boundary (APB) shearing to superlattice stacking fault (SSF) shearing as the temperature increases. The a/2<110> dislocations in matrix can pass through γ′ particles by dissociation or climbing at elevated temperature. In the temperature range of this study, {111}<110> and {111}<112> slips dominate the plastic deformation. The extended stacking fault (ESF) is the source of the microtwin, which crosses the individual grain and thickens with increasing temperature. In addition, a novel mechanism of ESF formation was observed, i.e., the Shockley shearing separated by one layer of atoms. Besides, the effect of Ta on tensile strength and plasticity in PM superalloys were discussed.

为满足先进航空发动机高压涡轮盘等热端部件的使用要求,需要研制更高性能的第四代粉末高温合金,其标志是最高使用温度要达到815℃.概述了最近10年来美国和英国第四代粉末高温合金的研究进展情况.重点介绍了美国高Ta含Hf的ME501合金和高W高Ta含Hf的TSNA-1合金,英国的高Co高Ta合金、高Ta低成本合金和高Nb的RRHT系合金的成分设计特点、组织及其稳定性、力学性能及抗氧化性.

人工道德智能体自主程度越来越高,其引发伦理困境的实质是自主机器系统的“技术偏见”与人类伦理价值的冲突.当前人工道德智能体的建构依赖的特定技术模型或伦理理论并不完善.价值敏感性设计为人工道德智能体的实现提供多维视角,是一种整体性、动态性的实践方法论.在该框架下,人类价值被系统性分析并被嵌入到人工道德智能体之中,但该方法仍待完善,以实现人工道德智能体与人类社会的合理互构.

随着当前金融科技的不断发展,商业银行传统经营发展方式和中介地位受到极大冲击和挑战.与此同时,在金融科技背景下的商业银行经过转型升级之后,积极与科技创新有效融合,有效防范金融风险,金融服务的覆盖面得到大力拓展,经营效益得到显著提升.然而,如何利用金融科技加强商业银行的创新与风险防控仍然值得认真研究和思考.本文就金融科技下商业银行的创新发展进行简要探析,分析了商业银行在金融科技背景下遇到的风险和挑战,提出了风险防控的对策.

针对新组装的多臂机需要对其可靠性进行检验,设计了一套多臂机控制及性能检测系统.通过分析多臂机工作原理,将嵌入式微控制器、花样数据存储器、变频器及电机驱动电路、多臂机电磁铁驱动电路、电磁铁磁性检测电路、电磁铁电流检测电路、多臂机摆臂运动检测电路以及网络通信接口功能模块集成在嵌入式电子多臂机控制及性能检测系统中,可以对电子多臂机的整体性能进行检测,给出了嵌入式电子多臂机控制系统的系统架构、硬件电路的设计和实现方法,软件系统的设计和实现方法.工厂实际应用表明,该系统能够用于控制及检测电子多臂机性能是否满足使用要求.

智能控制技术的不断进步与发展,使得其具有传统控制所无法比拟的特点,将其科学、合理的应用于各个领域之中,能够发挥较高的应用价值.就以机电一体化系统来说,智能控制技术融入其中,能够有效改善系统存在的各种缺陷,大大提高机电一体化系统的使用效果.那么,如何将智能控制技术有效应用于机电一体化系统中呢?本文将具体概述智能控制,明确其特点,进而探讨智能控制技术在机床、交流伺服系统及机器人中的应用,希望对于提高机电一体化系统的整体水平有所帮助.

<正>喊了多年的智能客厅的大生意,最终真的可能就被Chromecast这个小玩意儿给拿下了。北京时间7月25日,Google又开发布会了,最近科技公司的新产品发布会有点过多了,都是被苹果带坏了。可惜本次发布会的两大主角Android4.3和新Nexus7并无太多新意,只是常规升级。反倒是一个新的小东西——Chromecast,抢走了大家的眼球。

<正>在索尼、微软争相发布下一代游戏主机的时候,苹果也在觊觎这一市场。10月1号,科技界的爆料大神@evleaks在推特上发了一张照片,里面是一款罗技正在研制的iPhone专用游戏手柄,包括正反两面的图片。以爆料诺基亚Lumia系列手机而成名的@evleaks自从2011年从事这个行当以来已经泄露了超过200款设备的细节,可信度极高,经他爆料的设备或者新闻基本都被验证。因此可以断定这款iPhone的游戏配件在不久的将来就会上

<正>产品方向依附于大公司,产品迭代速度不够快,或者产品过于超前,三种创业公司的"死法"值得警惕。成功的创业公司都是类似的,必定是解决了客户的问题,并且以此产生了足够的收入。而失败的创业公司则各有各的失败原因,这些失败的教训也许比成功的经验对于其他创业者的学习价值更高。每一家成功的公司都有大量的报道,而失败的公司却很少获得媒体关注,因此笔者最近挖掘了一些失败的公司案例,之前已经写过两篇报道,分别分析了两家初创公司的创业经历。本文则选取了三个案例,意在用有限的篇幅,提供更多有用的信息。今

<正>在Android还在增加心脏(多核)和让心脏跳得更快(更高主频)的"邪路"上越走越远,而肾(电池)已经不堪重负的时候,iPhone5s选择了一个让手机和用户都能更"健康"的方向。新上市的iPhone5s吸引消费者的除了新的配色,还有指纹识别,新摄像头或者是第一个64位的手机处理器等噱头。而新增加的协处理器M7除了在发布会上被提了一下外,似乎大多数时候都被人忘记了。实际上这个小玩意儿不但将给iPhone带来不少新玩法,甚至能给穿戴式设备带来重大的影响。M7是什么东西?它能用来做什么?它是用来专门处理手机上各种传感器产生的数据的一个单独的处理器。就像显卡被用来处理图形方面的计算一样,M7将被用来处理传感器这些持续产生的的数据,将CPU从这些琐碎任务中解放出来。从iPhone第一代起,各种各样的传感器逐

7月22日,出品Ubuntu操作系统的Canonical公司在国际众筹平台Indiegogo上开始了为期一个月、筹款目标为3200万美元的项目:Ubuntu Edge.在筹款开始后的5个小时,该项目就已经收到了超过100万美元的资金,创造了众筹平台融资的最快记录,形势一片大好.

<正>在Email这种古老的领域里做出创新,其影响可能比探索一个新领域更大。Mailbox是2013年移动互联网的一个颇具传奇色彩的应用:号称是受著名邮箱客户端Sparrow和颇具创新精神的任务管理应用Clear的启发,Mailbox采取

<正>要想摆脱困境,东山再起,Zynga必须要动一次大手术。6月3号,社交游戏大厂Zynga宣布裁去占公司总员工数18%的520名员工,同时关闭了洛杉矶、达拉斯等地的几个工作室,包括一年前高价收购的你画我猜团队。Zynga从2年前的风光无限,发展到如今见诸媒体的全是股价重创、裁撤工作室之类的负面消息,这个活生生的盛极而衰的例子,值得我们反思一下。首先分析一下Zynga所处的外部

<正>Facebook home的真实目的在于,占领了用户的手机桌面,更方便地获取用户的隐私,收集来的这些数据将成为Facebook广告系统的基础。美国东部时间4月4号中午,Facebook召开了新产品发布会。官方发布了Facebook Home,一个在安卓系统上改变桌面的应用。安装之后用户的手机桌面将变成Facebook的照片流,用户可以

<正>索尼在智能化客厅领域相对完整的布局,可以为国内厂商提供借鉴。从索尼2月20日PS4发布会可见,新一代游戏机将会有几点大的变化:升级的硬件将带来更强大的机能和更高清的画质;新增的游戏视频、截图分享功能,将大大方便玩家将游戏相关内容发布到社交网络;云端计算使得主机和掌机PSVita联机游戏成为可能。另外,还有一点变化更值得注意

Coin的做法非常的机智,在传统支付和纯虚拟支付之间,找到了一个中间点. Coin,这个本意指硬币的英文单词近来异常火爆,因为比特币(BitCoin)的疯狂升值带来的交易狂潮.不过本文要介绍的Coin不是电子货币,而是由一家在旧金山的创业公司即将推出的名为“Coin”的电子信用卡.