金属材料外文翻译--950_热暴露对K403镍基合金组织和性能的影响【中文3090字】【PDF+中文WORD】
金属材料外文翻译-950_热暴露对K403镍基合金组织和性能的影响【中文3090字】【PDF+中文WORD】,中文3090字,PDF+中文WORD,金属材料,外文,翻译,950,暴露,K403,合金,组织,性能,影响,中文,3090,PDF,WORD
【中文3090字】950_热暴露对K403镍基合金组织和性能的影响刘军 杨合 孙志超 唐文婷1. 西北工业大学 凝固技术国家重点实验室,陕西 西安 7100722. 西安理工大学,陕西 西安 710048摘 要针对镍基铸造高温合K403,在950高温下分别进行了5、50和100h的热暴露试验,研究热暴露对K403合金显微组织和室温力学性能的影响。结果表明:K403合金经高温热暴露后,晶内和晶界析出M6C碳化物,相聚集长大且边角发生钝化,随热暴露时间的延长,出现相边角钝化变成圆形或近圆形,部分相发生定向相互连接粗化的现象和趋势;合金的名义屈服强度和抗拉强度随热暴露时间的延长而下降,而塑性则明显提高,导致合金强度下降塑性提高的主要原因之一则是强化相的聚集粗化;热暴露前后,室温拉伸断口均为枝晶组织断裂,热暴露后的试样拉伸断面出现少量沿晶断裂特征和浅而小的韧窝,且存在韧窝的数量随热暴露时间的延长而增多。关键词:镍基高温合金 K403;热暴露;力学性能;显微组织 作者简介:刘 君,女,1976 年生,博士生,讲师,西安理工大学材料科学与工程学院,陕西 西安 710048,电话:029-82312505,E-mail: xixyu163.comK403合金是镍-铬基铸造高温合金。它具有高温强度,耐疲劳性和铸造POS-自编码扩频通信性能。相较于其他合金,K403合金是更便宜的,并且较低钴含量(5)。作为镍基铸造高温合金之一,K403合金具有被广泛应用在各个领域,是轮转子低于900C等温锻造叶片成型模具预削硬变形的材料,Ti合金。一般是组合服务的条件下使用高温和载荷的轴承,这是一种非常苛刻的工作环境。在高温热曝光一定的时间周期长,结构变化将发生在合金中,包括聚集和强度的增长厄,甚至沉淀脆拓扑的密排(TCP)相。析出物的粗化被认为在蠕变性能的劣化的主要因素,AF-之热暴露。调查的850热暴露于微的影响结构不稳定性和IN738C的机械性能并得出结论认为,硬度和抗蠕变寿命脱该合金的过程中的长期热暴露折痕重从初级和次级粗化下降。研究长期热的影响暴露于相和一个方向的拉伸行倚重凝固镍基高温合金DZ951。结果表明屈服应力不断地与一个减小增加的老化时间在900下这源于粗化和降低体积分数。考虑到热暴露于高温合金的影响微观真实性的和特性,在本文中,镍基超级合金K403进行了详细研究了热暴露样品在950下不同时间的组织和性能。1实验镍基高温合金K403被熔化,在真空电感化炉。该合金熔化物倒入在测试棒真空的机械性能的测量,并接完标准的拉伸比杆用5毫米直径。该式样被放置在一个SX2-10-13室ELEC-TRIC炉,在空气中的热暴露在950维持5,50和100小时。拉伸实验,进行了关于一HT-2402-100kN的材料试验控制在室温下。观察显微组织,试样制备在腐蚀性液体混合10克硫酸铜450毫升盐酸,5毫升水 和80毫升蒸馏水。显微组织由GX71冶金显微镜和扫描型电子显微镜。拉伸断裂采用JSM-6700F扫描电子吉斯分析。图1 a.铸样品b.950下进行5小时的热暴露c.50小时热暴露d.100小时热暴露图2 K403合金碳化物形态后热暴露于 950下进行5小时2结果与讨论2.1热暴露对微观结构的影响图3显示K403合金的SEM图像之前和之后在950C热暴露不同的时间。图a所示热暴露前的铸样结构,主要由的固溶,相(+)共晶相,和MC阶段的固溶体为基体,它是有多个解决方案元素镍基奥氏体相(即钴,铬钼,和W)和连续分布的面心立方结构。分散相的体积,比例约58,是主要强化相,这是连贯沉淀在固态来自MA-矩阵。在(+)共晶相为液体沉淀为合金凝固后,用大花的形状和体积分数 的13。碳化物MC期可见和形状。图bd后热铸显示微观K403暴露在950C。在(+)的中心的网络共晶相显着降低,甚至消失AF-之三的热暴露(图1b),然后将共晶特征是不明显的热暴露后。在和相是 -来粗化明显,部分颗粒是面向与曝光时间的增加,如在图1c1D所示。 M6C颗粒从在分离TRA-晶体和晶界。图2示出了碳化物MI-微观结构的合金,5小时的热暴露后,其中,大批量主MC阶段,小M6C颗粒,和依稀可见M236沿着碳化物分布为链晶粒间界,使晶界卷绕。图3 微观结构和K403合金的相的形貌 在不同的条件(a)铸态试样,(b)样品 在950热暴露5小时(c),50小时(d)和100小时作为主要强化相,相是镍3AL-系金属间化合物。其数量,形态,大小和分布起着重要的作用,确定正确的合金的关系。在950C的热暴露有两种形态和相的大小的变化,如图中所示。在铸造条件下。在热暴露时相让一起长大的钝立方角(图b)。由于热暴露的增加,球形或近时间的相的球形形状从钝边角形成,与一些相扎堆沿滑移面,往往-ING形成条纹形状,由于面向连接和无粗化效果(图cd)态变化相可以通过竞争机制来解释致的接口和晶格弹性能。作为热暴露的继续,相粗大化的/相的匹配程度降低,并且弹性应变能降低。因此,该界面能源在确定的变化起主导作用。该界面能量正比于/ 的界面面积阶段,也就是说,W = A ,其中W ,和A是在界面能,具体界面能和界面面积的/相。合金的结构演化通过的总能量中的合金系的减少驱动。球体的面积比的立方体的体积更小,所以在该/与界面的还原界面能减小 面积,有利于对总能量的减少合金体系。因此,该相的角变得迟钝,最后更改为近球形。2.2力学性能的热暴露的影响表1列出的流延的室温抗拉性能在950C的热暴露后不同K403合金时间。铸态合金的高强度和低塑性。随着时间的增加在热暴露过程中,将偏置屈服应力,拉伸强度下降。例如,根据在950热暴露100小时后,偏置屈服应力为732兆帕,拉伸强度994兆帕,而26.5和10.1下降为较那些(996和1106兆帕)热暴露前。与此相反,塑性,可以明显提高。伸长率是用于合金10.1热暴露100小时,它是由2.81倍升高 作为(2.65),热暴露前的强度降低提高可塑性被认为要的K403合金的微观结构的变化,结果热暴露后,如上所讨论。热暴露在高温下,粗化和聚集和相将发生导致该合金折痕晶格失配其结果是,电阻减小对于位错在相切割运动,所以该合金的强度下降。另一方面,晶粒边界看起来像一个链有许多细小的碳化物颗粒从内部晶粒和晶界沉淀,这不仅降低了启动和PROPA-的倾向裂纹,而且还提高合金的塑性。另外,粗大的相,使 通道更宽,从而使位错可以更容易地移动这是有益的合金的塑性变形和导致伸长率的提高。在一个单词时,相粗糙度是提高合金的塑性有用。表1 K403合金的不同热暴露时间后的拉伸性能条件0.2/MPab/MPa/%As-cast99611062.65950 5h92010473.71950 50h77710049.15950 100h73099410.12.3暴露对拉伸断裂的行为室温拉伸断口形貌 的铸态K403合金暴露在950进行不同时间。宏观断口表面是比较光滑 铸态K403合金无热辐射,这是每相垂直的拉伸负荷的方向。没有明显的剪切唇区。整个断裂面显示一个结构断裂。有“河形图案”和二次裂纹的横截面。图4 K403基地的室温拉伸断口形貌在不同的条件(a,b)宏观和微观结构的铸态样品,(cf)后的热曝光确保在950下5小时,50小时,100小时.对于在950下5小时的热暴露后表明,该表面是不平衡的,粗糙的有明显的撕裂区(图4c)。另外,一定量的浅凹坑分布在断裂面(图4d)。热后断裂面曝光仍是树枝状结构断裂性质。如热暴露时间增加,晶界压裂功能,可以观察到。还有更多的断裂面,显示的外观可塑性特征(图4e和4023)。合金的延伸率是也增强据此。3结论(1)在不同条件下,热曝露不一定时间,随着时间的增加,抵消屈服应力和K403合金的拉伸强度降低,而塑性明显提高。而100小时,热暴露后的26.5偏置屈服应力,拉伸强度下降 和10.1,分别同时伸长率增加2.81倍。(2)在950下热暴露为5,50和100小时后,在(+)相在K403合金的共晶特征趋向是不明显的,M6C碳化物从沉淀TRA-晶粒和晶粒边界,并在相的角正在减弱。相的增加聚合与球形或近球形长大形状和相的组成部分有倾向。该的聚集和粗化“加强相导致合金的强度降低。(3)两个铸态K403合金和那些与热曝露在950C的很长一段时间(例如,5,50,和100小时)树枝状结构断裂特性的室温断裂面。(4)随着时间的增加晶间断裂。 Rare Metal Materials and Engineering Volume 42,Issue 6,June 2013 Online English edition of the Chinese language journal Cite this article as:Rare Metal Materials and Engineering,2013,42(6):1123-1126.Received date:June 15,2012 Foundation item:NSFC(50735005);National“973”Project(2010CB731701);Xian Science and Technology Planning Projects(CX12180-8);Science Research Pro-ject of Xian University of Technology(101-211009)Corresponding author:Yang He,Ph.D.,Professor,State Key Laboratory of Solidification Professing,Northwestern Polytechnical University,Xian 710072,P.R.China,Tel:0086-29-88495632,E-mail: Copyright 2013,Northwest Institute for Nonferrous Metal Research.Published by Elsevier BV.All rights reserved.ARTICLE1123 Effect of 950 C Thermal Exposure on Microstructures and Properties of Ni-Based K403 Alloys Effect of 950 C Thermal Exposure on Microstructures and Properties of Ni-Based K403 Alloys Liu Jun1,2,Yang He1,Sun Zhichao1,Tang Wenting2 1 State Key Laboratory of Solidification Processing,Northwestern Polytechnical University,Xian 710072,China;2 Xian University of Technology,Xian 710048,China Abstract:Thermal exposure experiments of Ni-based cast superalloy K403 at 950 C for 5,50 and 100 h were conducted.The effect of thermal exposure on the microstructures and room-temperature mechanical properties of the superalloys K403 was studied.The results show that M6C carbides segregate from intra-grains and grain boundaries,and phases aggregate and grow up with blunted corners.With increasing of thermal exposure time,on the one hand,phases of spherical or nearly spherical shapes are formed from blunted corners and parts of the phase tend to coarsen due to the connection-oriented effect.On the other hand,the offset yielding stress and the tensile strength decrease,while the plasticity improves obviously,resulting from the aggregation and coarsening of the strengthening phase.The room-temperature tensile fracture surface is characterized by the dendritic structure fracture for K403 al-loys before and after the thermal exposure.Whereas the intercrystalline fracture feature,and the shallow and small dimples appear on the tensile section of the thermal-exposed alloys.And the amount of dimples increases as the exposure time increases.Key words:Ni-based K403 superalloy;thermal exposure;mechanical property;microstructures The K403 alloy is a Ni-Cr based cast superalloy strength-ened by several elements including Co,W,Mo,Al,and Ti.It high-temperature strength,fatigue resistance and casting pos-sess properties.Compared to other alloys with similar proper-ties,the K403 alloy is cheaper due to lower Co content(5%).As one of the nickel-base cast superalloys,the K403 alloy has been widely used in various fields,including gas turbine guide vanes with working temperatures below 1000 C,turbine rotor blades below 900 C,isothermal forging forming dies to pre-pare the hard deformation materials such as Ti alloys,and other parts with the high working temperatures.This kind of parts is generally used under composite service conditions with high temperature and load bearing,which is a very harsh working ambient.Under the high-temperature thermal expo-sure for a long period of time,structural changes will occur in alloys,including the aggregation and the growth of strength-ening phases1-6,precipitation and transformation of car-bides7,8,and even precipitation of brittle topologically close-packed(TCP)phases1,9,which cause the deterioration of mechanical properties of superalloys and so reduce their service life and reliability.Acharya and Fushs1 studied the effect of long-term thermal exposure on the microstructure and properties of CMSX-10 single crystal nickel-base super-alloy.The coarsening of the precipitates was considered to be a main factor in the degradation of the creep properties af-ter thermal exposure.Aghaie-Khafr and Hajjavady2 investi-gated the effect of 850 C thermal exposure on the micro-structural instability and the mechanical properties of IN738C and concluded that the hardness and the creep lifetime de-crease of the alloy during long-term thermal exposures re-sulted from coarsening of primary and secondary precipi-tates.Xia et al4,5 investigated the effect of long-term thermal exposure on the phase and the tensile behavior of a direc-tionally solidified nickel-base superalloy DZ951.The results showed that the yield stress continuously decreases with an increase of aging time at 900 C.This arises from the Liu Jun et al./Rare Metal Materials and Engineering,2013,42(6):1123-1126 1124coarsening and decrease in the volume fraction.Considering the effect of thermal exposure on the superalloy microstruc-tures and the properties,in this paper,Ni-based superalloys K403 were studied in detail by thermal exposure samples at 950 C for different time.1 Experiment1 Experiment Ni-based superalloys K403 were melted in a vacuum induc-tion furnace.The alloy melting was poured into test bars in vacuum for the measurements of mechanical properties,and then finished to standard stretching-ratio bars with 5 mm in diameter.The bars were placed in a SX2-10-13 chamber elec-tric furnace for the thermal exposure in air at 950 C for 5,50,and 100 h.The tensile experiments were carried out on a HT-2402-100kN material testing machine with the computer servo control at room temperature.To observe microstructures,the specimens were prepared in a corrosive liquid mixed with 10 g CuSO4,50 mL HCl,5 mL H2SO4,and 80 mL distilled water.The microstructures were investigated by a GX71 in-verted metallurgic microscope and a ZEISS-SUPRATM55 scanning electron microscope.The tensile fracture morpholo-gies were analyzed using a JSM-6700F scanning electron mi-croscope.2 Results and Discussion2 Results and Discussion 2.1 Effect of thermal exposure on the microstructure Fig.1 shows SEM images of K403 alloys before and after thermal exposure at 950 C for different time.Fig.1a shows the as cast sample structure before thermal exposure,main consisting of solid solution,phase,(+)eutectic phase,and MC phase.The solid solution is the matrix,which is the Ni-based austenite phase with multiple solution elements(i.e.,Co,Cr,Mo,and W)and continuously-distributed face-centred cubic structure.The small and dispered phase with the vol-ume fraction about 58%is the main strengthening phase,which is precipitated coherently in solid state from the ma-trix.The(+)eutectic phase is the liquid precipitation as the alloy is solidified,with a big flower shape and volume fraction of 1%3%.The carbide MC phase shows bulk and bar shapes.Fig.1b1d show cast K403 microstructures after thermal exposure at 950 C.The network in the center of the(+)eutectic phase dramatically decreases and even disappears af-ter thermal exposure(Fig.1b),and then the eutectic features are unobvious after thermal exposure.The and phases be-come coarsening obviously and some of particles are con-nection-oriented with increasing of the exposure time,as shown in Fig.1c1d.M6C particles segregate from the in-tra-crystals and grain boundaries.Fig.2 shows the carbide mi-crostructures in the alloys after thermal exposure for 5 h,wherein the big-bulk primary MC phases,small M6C particles,and faintly visible M23C6 carbides distribute as chains along the grain boundaries,which make the grain boundary winding.As a main strengthening phase,the phase is a Ni3Al-Fig.1 Microstructures of K403 alloy under different conditions:(a)as-cast sample,(b-d)after thermal exposure at 950 C for 5 h(b),50 h(c),and 100 h(d)Fig.2 Carbide morphology of K403 alloy after thermal expose at 950 C for 5 h based intermetallic compound.Its quantity,morphology,size,and distribution play an important role in determining proper-ties of alloys10,11.During the thermal exposure at 950 C,there are changes for both morphology and size of the phase,as shown in Fig.3.In the casting condition,the phase is cu-bic(Fig.3a).During the thermal exposure,the phases get together to grow up with blunt cubic corners(Fig.3b).As the time of thermal exposure increases,spherical or nearly-spherical shapes of phases form from the blunted corners,and some of phases get together along the slip plane,tend-ing to form striped shapes due to the connection-oriented and coarsening effects(Fig.3c3d).The morphology change of the phase can be explained by the competition mechanism of elastic energies induced by the interface and lattice mis-match12.As the thermal exposure continues,the phase coarsens,the mismatch degree of/phases decreases,and the elastic strain energy decreases.Therefore,the interfacial energy plays a leading role in determining of the changes.The interfacial energy is proportional to the interfacial area of/phases13,that is to say,W=A,where W,and A are the in-terfacial energy,specific interfacial energy,and interfacial area of/phases,respectively.The structure evolution of alloys is a(+)MCbc d10 m20 mLiu Jun et al./Rare Metal Materials and Engineering,2013,42(6):1123-1126 1125 Fig.3 Microstructures and morphologies of phase of K403 alloy on different conditions:(a)as-cast sample,(b-d)samples after thermal exposure at 950 C for 5 h(b),50 h(c),and 100 h(d)driven by the reduction of the total energy in the alloy system.A area of a sphere is smaller than that of a cube,so the/in-terfacial energy decreases with the reduction of the interfacial area,which benefits to the reduction of the total energy in the alloy system.Therefore,the corner of the phase becomes blunted and finally changes to the nearly spherical morphol-ogy after thermal exposure.2.2 Effect of thermal exposure on mechanical properties Table 1 lists the room-temperature tensile properties of cast K403 alloys after thermal exposure at 950 C for different time.The as-cast alloys are of high strength and low plasticity.As the time increases in the thermal exposure process,the offset yielding stress and the tensile strength decrease.For example,under the thermal exposure at 950 C for 100 h,the offset yielding stress is 732 MPa and the tensile strength is 994 MPa,which drop by 26.5%and 10.1%as compared with those(996 and 1106 MPa)before thermal exposure,respec-tively.In contrast,the plasticity can be enhanced evidently after thermal exposure.The elongation is 10.1%for alloys thermally exposed for 100 h,which is elevated by 2.81 times as that(2.65%)before thermal exposure.The reduced strength and enhanced plasticity are believed to be the results of the microstructure changes of K403 alloys after thermal exposure,as discussed above.Under the thermal exposure at high temperatures,the coarsening and aggregation of and phases will occur in the alloys leading to the de-crease of lattice misfit.As a result,the resistance is reduced for the dislocation cutting motion in the phase,so the strength of the alloy descends.On the other hand,the grain boundary looks like a chain with many fine carbide particles precipitating from intra-grains and grain boundaries(Fig.2),which not only reduces the tendency of initiation and propa-gation of cracks,but also improves the plasticity of alloys ef-fectively.In addition,the coarsening phase makes the channel wider,so that the dislocation can move more easily,Table 1 Tensile properties of K403 alloys after thermal exposure different time Conditions 0.2/MPa b/MPa/%As-cast 996 1106 2.65 950 C,5 h 920 1047 3.71 950 C,50 h 777 1004 9.15 950 C,100 h 732 994 10.1 which is beneficial to the plastic deformation of alloys and leads to the improvement of elongation.In a word,the phase coarseness is helpful to improve the plasticity of alloys8,14.2.3 Effect of thermal exposure on tensile fracture behav-iors Fig.4 shows room-temperature tensile fracture morphologies of as-cast K403 alloys exposed at 950 C for different time.The macroscopic fracture surface is relatively smooth for as-cast K403 alloys without thermal exposure,which is per-pendicular to the tensile load direction.No obvious shear lip zone is observed.The whole fracture surface displays a den-dritic structure fracture.It can be seen that there are“river shape patterns”and secondary cracks in the cross-section im-ages,suggesting the main cleavage fractures(Fig.4a and 4b).Neither obvious plastic deformation before fracture nor neck-ing around the fracture is observed,which reveals the brittle fracture feature.The macroscopic fracture images of alloys Fig.4 Room-temperature tensile fracture morphologies of K403 al-loy on different conditions:(a,b)macro-and micro-structures of as-cast samples,respectively.(cf)after the thermal expo-sure at 950 C for 5 h(macro-)(c),5 h(micro-)(d),50 h(e),and 100 h(f),respectively a bc d1 ma bc de fLiu Jun et al./Rare Metal Materials and Engineering,2013,42(6):1123-1126 1126after thermal exposure for 5 h at 950 C show that the surface is uneven and rough with obvious tearing zones(Fig.4c).Also,a certain amount of shallow dimples are distributed in the fracture surface(Fig.4d).The fracture surface after thermal exposure is still of the dendritic structure fracture nature.As the time of thermal exposure increases,the intergranular frac-ture feature can be observed.There are more dimples distrib-uted on the fracture surface,indicating the appearance of the plasticity feature(Fig.4e and 4f).The elongation of alloys is also enhanced accordingly,as listed in Table 1.3 Conclusions 3 Conclusions 1)On different conditions 950 C,different thermal expo-sure time as the time increases,the offset yielding stress and tensile strength of K403 alloy are reduced,while the plasticity is improved obviously.After thermal exposure for 100 h,the offset yielding stress and tensile strength decrease by 26.5%and 10.1%,respectively,while the elongation increases by 2.81 times.2)After thermal exposure at 950 C for 5,50,and 100 h,the eutectic features of the(+)phase in the K403 alloy tend to be unobvious,the M6C carbides precipitate from in-tra-grains and grain boundaries,and the corners of the phase are blunted.With the increase of exposure time,the phase aggregates to grow up with spherical or nearly spherical shapes,and parts of the phase have the tendency of coars-ening.The aggregation and coarsening of the strengthening phase result in the decrease of the strength of the alloy.3)Both the as-cast K403 alloys and those with thermal ex-posure at 950 C for a long time(e.g.,5,50,and 100 h)exhibit dendritic structure fracture features on room-temperature ten-sile fracture surfaces.Dimples appear on the tensile section of specimens after thermal exposure.As the time increases,the intercrystalline fracture behavior is observed and the amount of dimples increases.ReferencesReferences 1 Acharya M V,Fuchs G E.Materials Science and Engineering A J,2004,381:143 2 Aghaie-Khafri M,Hajjavady M.Materials Science and Engi-neering AJ,2008,487:388 3 Han G W,Zhang Y Y.Materials Science and Engineering AJ,2006,441:253 4 Xia P C,Yu J J,Sun X F et al.Materials CharacterizationJ,2007,58:645 5 Xia P C,Yu a J J,Suna X F et al.Journal of Alloys and Com-poundsJ,2007,443:125 6 Chen Jingyang(陈晶阳),Hu Pinpin(胡聘聘),Feng Qiang(冯 强)et al.Rare Metal Materials and Engineering(稀有金属材料与工程)J,2011,40(12):2111 7 Deodeshmukh V P,Srivastava S K.Materials and DesignJ,2010,31:2501 8 Qin Xuezhi(秦学智),Guo Jianting(郭建亭),Yuan Chao(袁 超)et al.Acta Metallurgica Sinica(金属学报)J,2010,46(2):213 9 Yang J X,Zheng Q,Sun X F et al.Materials Science and Engi-neering AJ,2007,465:100 10 Ai S H,Lupinc V,Onofrio G.Scripta Metallurgica et Materi-aliaJ,1993,29:1385 11 Murakumo T,Kobayashi T,Koizumi Y et al.Acta MaterialliaJ,2004,52:3737 12 Dye D,Stone H J,Reed R C.Acta MaterialiaJ,2001,49:1271 13 Zhuo Jianbo(周建波),Li Dianguo(李殿国),Cui Chunxiang(崔春翔).Journal of Materials Engineering SP(材料工程)J,2006,(s1):196 14 Zhou Lanzhang,Lupinc Valentino,Guo Jianting.Journal of Ma-terials Science and TechnologyJ,2001,17(6):633 950 热暴露对 K403 镍基合金组织和性能的影响 刘 君1,2,杨 合1,孙志超1,唐文亭2(1.西北工业大学 凝固技术国家重点实验室,陕西 西安 710072)(2.西安理工大学,陕西 西安 710048)摘 要:针对镍基铸造高温合金 K403,在 950 高温下分别进行了 5、50 和 100 h 的热暴露试验,研究热暴露对 K403 合金显微组织和室温力学性能的影响。结果表明:K403 合金经高温热暴露后,晶内和晶界析出 M6C 碳化物,相聚集长大且边角发生钝化,随热暴露时间的延长,出现相边角钝化变成圆形或近圆形,部分相发生定向相互连接粗化的现象和趋势;合金的名义屈服强度和抗拉强度随热暴露时间的延长而下降,而塑性则明显提高,导致合金强度下降塑性提高的主要原因之一则是强化相的聚集粗化;热暴露前后,室温拉伸断口均为枝晶组织断裂,热暴露后的试样拉伸断面出现少量沿晶断裂特征和浅而小的韧窝,且存在韧窝的数量随热暴露时间的延长而增多。关键词:镍基高温合金 K403;热暴露;力学性能;显微组织 作者简介:刘 君,女,1976 年生,博士生,讲师,西安理工大学材料科学与工程学院,陕西 西安 710048,电话:029-82312505,E-mail:
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