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Fe—Cr—Mn(Ni)合金抗辐照损伤特性研究 总被引:1,自引:0,他引:1
电子束辐照结果证明,Fe-Cr-Mn合金辐照损伤行为不同于Fe-Cr-Ni合金,因为溶质原子与点缺陷有相互作用,特别是Mn原子与空位相互作用比Ni原子来得强烈,致使Fe-Cr-Mn合金中空位迁移激活能比Fe-Cr-Ni合金高。Ni,Mn在合金中扩散行为不同,是造成两种合金辐射照损伤行为不同的原因。 相似文献
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研究了热处理后前后变形Ni-Cu-Fe-Mn-Si合金中的Si的存在形式,在晶界及晶内的分布状态和结构,并研究了在热处理状态下,合金性能的变化,XRD分析表明:Ni-Cu-Fe-Mn-Si合金基体为面心方立结构,在热加工状态(R态)下,Ni-Cu-Fe-Mn-Si合金除Ni3Si相外,还出现了Ni31Si12相。该相为立方结构。TEM分析表明:第二相(Ni3Si)在晶界和晶内弥散分布,少量在晶界聚 相似文献
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对低Al,高Ti,Nb(合金A)和高Al、低Ti,Nb(合金B)两种成分特征的Fe-Ni-Cr-Co-Nb-Ti-Al合金宏观和微观铸态组织的观察分析表明,合金A凝固速度较快,柱状晶区较大;两者枝晶间及铸态晶界上都分布着较多块(厚片)状富含Nb和Ti的MC和Laves相多晶体;合金B柱状晶区晶界Laves相较多;合金A晶界MC和Laves相附近析 体状γ′和η相及胞状η相;合金BKγ′的尺寸仅约为 相似文献
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激光熔覆Fe—Cr—W—Ni—C合金的微观组织及其演化 总被引:11,自引:0,他引:11
用SEM,ATEM及化学分析、显微硬度测定等手段,对激光熔覆Fe-Cr-W-Ni-C(其质量比为10:5:1:1:1)合金的微观组织进行了研究。结果表明,该合金经激光熔覆后可得到亚共晶和过共晶两类熔覆组织为γ+(γ+M7C3)及M7C3+(γ+M7C3),存在领先相的竞争与选择,γ为亚稳奥氏体,具有较高的合金元素过饱和含量;M7C3(M=Cr,Fe,W等)为Cr基合金碳化物。存在层片状、蜂窝状、网 相似文献
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利用ATEM研究了铁基金元合金Fe-Cr-W-Ni-C激光熔覆层的微观组织,亚稳相结构特征以及高温时效时的亚相变转机制。结果表明组织为亚共晶组织,即γ+(γ+MC),γ-奥氏体为具有较高合金度的过饱和亚稳相,M7C3(M为Cr,Fe,W)为六方结构的Cr基亚稳合金碳化物。 相似文献
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应用电镜及X线衍射技术,研究了高温下Ni_(75)Al_(16.6)Cr_(7.84)Zr_(0.45)B_(0.1)Mg_(0.01)合金晶界失效行为。经1180℃保温,由于偏聚晶界区Mg含量(at.-%)达15-19。同时Zr含量(at,-%)明显增大可达28-33;并观察到局部晶界共晶熔化现象。通过1000℃固溶及变温热循环处理,合金中晶内出现CrN相沉淀,沿晶界有Cr2(C,N)相析出。 相似文献
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NiAl—28Cr—5Mo—1Hf多相金属间化合物的显微组织及力学性能研究 总被引:10,自引:0,他引:10
研究了铸造和HIP处理NiAl-28Cr-5Mo-1Hf(原子分数,%,下)金属间化合物的显微组织,铸造合金是由NiAl,Cr(Mo)和Ni2AlHf相组成,经1250℃,200MPa,4.5hHIP处理后。 相似文献
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HU Benfu University of Science Technology Beijing Beijing ChinaTAKAHASHI Heishichiro ITOH Hisatoshi TAKEYAMA Taro Hokkaido University Sapporo Japan Associate Professor Dept of Materials Science Engineering University of Science Technology Beijing Beijing China 《金属学报(英文版)》1990,3(4):229-235
The behavior of void swelling and segregation in Fe-15Cr-xMn alloys and an alloy con-taining small amount of W and V was investigated by electron-irradiation.The compositionalanalysis in the irradiated regions including grain boundaries was performed.The resultdts showthat there are many common features of irradiuation tehavior in the Fe-Cr-Mn andFe-Cr-Ni systems while there are some significant differences,In the Fe-Cr-Mn alloy sys-tems void swelling was rematrkably suppressed and at the same time the radiation-inducedsegregation was also retarded,furthermore,the segregation was strongly retarded in anFe-15Cr-15Mn alloy containing small amount of W and V.The results also show that Ni re-placed by Mn does not in general confer immunity from either swelling or phase instabilities.The phase instability is due to the different diffusion behavior of Ni and Mn in reponse to theoperation of the inverse-Kirkendall effecr.Fe segregates to the microstructural sinks in theFe-Cr-Mn alloys.The segregation of Fe often leads to the formation of ferrite.This fact isbeneficial to reducing the swelling rate and segregation on the grain boundaries. 相似文献
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采用超高压电镜与离子加速器相连结的复合辐照装置,研究了注He对低活性Fe-Cr-Mn(W,V)合金辐照产生的点缺陷及二次缺陷行为的影响.实验结果表明:辐照初期形成的点缺陷与He相互作用,进而影响二次缺陷(位错、位错环和空洞)的形成;He明显促进位错密度增大和空洞核心形成,并导致空洞肿胀增加.对辐照产生的点缺陷与He相互作用的机理进行了理论分析。 相似文献
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R.G. Faulkner 《金属学报(英文版)》2003,16(5):365-374
Irradiation-induced grain boundary segregation of solute atoms frequently bring about grain boundary precipitation of a second phase because of its making the solubility limit of the solute surpassed at grain boundaries. Until now the kinetic models for irradiation-induced grain boundary precipitation have been sparse. For this reason, we have theoretically treated grain boundary precipitation under irradiation in dilute binary alloys. Predictions of γ' -Ni3Si precipitation at grain boundaries are made for a dilute Ni-Si alloy subjected to irradiation. It is demonstrated that grain boundary silicon segregation under irradiation may lead to grain boundary γ'-Ni3Si precipitation over a certain temperature range. 相似文献
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《Acta Materialia》2001,49(2):289-298
Impurity effects were investigated in an Ir alloy of nominal composition Ir–0.3 W–0.006 Th–0.005 Al1. The impurities that were added included Fe, Ni, Cr, Al, and Si, at levels ranging from 50 to 5000 ppm. Of the elements investigated (impurities as well as alloying additions), only Si and Th were found to segregate to the grain boundaries. In alloys doped with low levels of Si (<200 ppm), both Si and Th segregated to the grant boundaries. In addition, Th-containing precipitates were identified in these alloys, but not Si-containing precipitates. When added at higher bulk levels, Si displaced (beneficial) Th from the boundaries. This caused the segregated Th at the boundaries to decrease (to practically zero) when the amount of grain-boundary Si increased (to its saturation level). Silicon also reacted with Th to form Ir–Th–Si precipitates and promoted the formation of a low-melting eutectic on the grain boundaries of the highest Si alloys. As for the other elements, not only did they not segregate to the grain boundaries, but they also did not affect Th segregation. Together, these results explain why Fe, Ni, Cr, Al (and Si at low levels) do not embrittle iridium, whereas Si at high levels causes severe embrittlement. 相似文献
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It is essential for materials used at high‐temperatures in corrosive atmosphere to maintain their specific properties, such as good creep resistance, long fatigue life and sufficient high‐temperature corrosion resistance. Usually, the corrosion resistance results from the formation of a protective scale with very low porosity, good adherence, high mechanical and thermodynamic stability and slow growth rate. Standard engineering materials in power generation technology are low‐Cr steels. However, steels with higher Cr content, e.g., austenitic steels, or Ni‐base alloys are used for components applied to more severe service conditions, e.g., more aggressive atmospheres and higher temperatures. Three categories of alloys were investigated in this study. These materials were oxidised in laboratory air at temperatures of 550°C in the case of low‐alloy steels, 750°C in the case of an austenitic steel (TP347) and up to 1000°C in the case of the Ni‐base superalloys Inconel 625 Si and Inconel 718. Emphasis was put on the role of grain size on the internal and external oxidation processes. For this purpose various grain sizes were established by means of recrystallization heat treatment. In the case of low‐Cr steels, thermogravimetric measurements revealed a substantially higher mass gain for steels with smaller grain sizes. This observation was attributed to the role of alloy grain boundaries as short‐circuit diffusion paths for inward oxygen transport. For the austenitic steel, the situation is the other way round. The scale formed on specimens with smaller grain size consists mainly of Cr2O3 with some FeCr2O4 at localized sites, while for specimens with larger grain size a non‐protective Fe oxide scale is formed. This finding supports the idea that substrate grain boundaries accelerate the chromium supply to the oxide/alloy phase interface. Finally, in the Ni‐base superalloys deep intergranular oxidation attack was observed, taking place preferentially along random high‐angle grain boundaries. 相似文献
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TiAl基合金双态组织的控制 总被引:3,自引:0,他引:3
研究了TiAl合金双态组织的显微组织参数对力学性能的影响 ,通过对Ti 46 5Al 2Cr 1 5Nb 1V金属间化合物进行特定的热处理 ;分别获得了具有相同晶粒大小、不同片层晶粒体积分数 ,以及相同片层晶粒体积分数、不同晶粒大小显微组织的两个系列的双态复相TiAl合金。研究结果表明 :对于双态复相组织 ,晶粒尺寸由预备热处理过程中的退火时间来控制 ;而片层晶粒体积分数则通过后续热处理温度来控制 ,不同片层晶粒含量双态组织的晶粒尺度可以通过后续热处理时间来控制 相似文献