文矛
,
林栋梁
金属学报
本文利用透射电镜观察了定向凝固高温合金DS Rene80在拉伸及蠕变时的位错亚结构。试验结果表明:在低于760℃拉伸时,切割γ′粒子的是在{111}面上夹有APB的(1/2)〈110〉位错对。在不低于760℃拉伸时,切割γ′粒子的是在{111}面上夹有超点阵内禀层错(SISF)γ(1/3)〈112〉不全位错;这些不全位错在大应力的作用下于{111}面上将分解为一根(1/2)〈110〉螺位错和一根(1/6)〈112〉刃位错,并在其间夹有一个APB。在760℃,618MPa条件下蠕变时,切割γ′粒子的是在{111}面上夹有SISF的(1/3)〈112〉不全位错;这些不全位错此时不分解。与此同时,亦有(1/2)〈110〉位错对切割γ粒子。在980℃,190MPa条件下蠕变时,则无γ′粒子被切割的现象。在760℃,618MPa及980℃,190MPa条件下蠕变至第二阶段时,在γ/γ′界面上都形成了二维位错网络墙,墙上位错的攀移是合金形变的控制因素。第二阶段蠕变速率(ε)与立方γ′粒子的尺寸(α)和体积分数(V_f)的关系符合ε∝α/V_f~(2/3)
关键词:
定向凝固
,
Ni-base superalloy
,
plastic deformation
,
r'-phase
Jianping NIU
,
Kenu YANG
,
Tao JIN
,
Xiaofeng SUN
,
Hengrong GUAN
,
Zhuangqi HU
材料科学技术（英文）
The variation of S content during VIM refining Ni-base superalloy using CaO crucible was studied. It was found that the desulphurization process could not be carried out by only using CaO crucible. The role of Al addition to desulphurization was also studied. Combining with the results of XRD and composition analysis of the CaO crucible, the mechanism of desulphurization was proposed. Thermodynamical calculation about the reaction between the interface of CaO crucible and liquid metal has been discussed. This work indicated that under proper refining technology the S content in the liquid Ni-base alloy could be reduced from 3×10-5 to 2×10-6-4×10-6.
关键词:
Ni-base superalloy
,
null
,
null
,
null
ZHANG Yuanhu ZHANG Yun HU Gengxiang Shanghai Jiaotong University
,
Shanghai
,
China
金属学报(英文版)
An investigation was made on the creep crack growth behaviour under static load at 1023 K for Ni-base superalloy GH30 exposed to air and air+10% SO_2.The results showed that in the region of low stress intensity factor,the creep crack growth rate is higher in air+10% SO_2 than in air only,while in the high region,it is reverse.The fractograph of specimens has been analyzed,and the mechanism of creep crack growth together with the influences of sul- phur and oxygen has been discussed as well.
关键词:
Ni-base superalloy
,
null
,
null
,
null
HUANG Qianyao SHI Yanyu Central Iron and Steel Research Institute
,
Ministry of Metallurgical Industry
,
Beijing
,
China Department No.5
,
Central Iron and Steel Research Institute
,
Ministry of Metallurgical Industry
,
Beijing
,
China
金属学报(英文版)
The quantitative analytical method combining the electrolytic extraction with X-ray diffraction analysis to determine the carbides and TCP in a Ni-base superalloy was developed.The variation of decomposition of MC and precipitation of M_(23)C_6 and M_6C with hot exposure time at 850—1000℃ is shown to conform to hyperbolic law.The elemental con- stitution of M_(23)C_6 changes continutously during the hot exposure process.At the primary stage the constitution of the precipitates is(Cr_(0.67)Mo_(0.13)Ni_(0.13)Co_(0.07))_(23)C_6.Then with in- creasing Cr and decreasing Mo,Ni and Co it finally becomes(Cr_(0.88)Mo_(0.07)Ni_(0.03)Co_(0.02))_(23)C_6. The higher the hot exposure temperature,the faster the final constitution of M_(23)C_6 may be achieved.
关键词:
Ni-base superalloy
,
null
,
null
,
null
,
null
王福会
,
楼翰一
,
白林祥
金属学报
本文用含钇的特殊料浆做底层,用Cr-Al料浆做保护层,在1060℃氩气保护下保温1h,获得了含稀土钇的涂层。电子探针微区成分分析结果表明,钇存在于涂层的中间部位并以Ni_5Y金属间化合物的形式存在。1000℃空气中氧化结果表明,一次Al-Y共渗涂层抗氧化性能很差,涂层中出现了大量的钇和铝的内氧化。经二次渗铝的Al-Y共渗涂层的抗氧化性能明显优于单渗铝涂层。
关键词:
Al-Y共渗涂层
,
anti-oxidation property
,
Ni-base superalloy
YANG Wangyue
,
ZHANG Jishan
,
CHEN Guoliang
,
TIAN Shusen
,
GENG Qingquan Beijing University of Iron and Steel Technology
,
Beijing
,
China. Institute of Metal Research
,
Academia Sinica. Fushun Steel Works
,
Fushun
,
Liaoning
,
China.
材料科学技术（英文）
The deformation and fracture behaviour of nickel-base superalloy GH698 with different grain size have been studied at 700℃ under fatigue-creep interaction conditions. Compared with coarse-grained specimens, the grain refining process shows obvious effect on the mechanical behaviour of the alloy, i. e. in F and C zones, the fraction of pure fatigue and creep fracture on fracture surfaces is greatly reduced, which decreases and increases the fracture life in zones F and C respectively, in FC and C zones, creep deformation is greatly restrained by the alternating stress component, which increases the fracture life remarkably. It is also proved that in spite of the difference in microstru- tures such as grain size, for a constant tem- perature, a unique life equation t_r=A~n can be used to predict rupture life within the stress region controlled by the same fracture mode.
关键词:
Ni-base superalloy
,
null
,
null
ZHENG Yunrong RUAN Zhongci Institute of Aeronautical Materials
,
Beijing
,
China ZHENG Yunrong
,
Senior Engineer
,
Laboratory No.4 Institute of Aeronautical Materials
金属学报(英文版)
In consideration of the envelopment of γ dendrites by the Hf-rich melts at the late period of solidification of the cast Ni-base superalloys containing Hf,a heat of brazing filler alloy composed of Ni-18.6Co-4.5Cr-4.7 W-25.6Hf(wt-%)was prepared.This alloy is hypereutectic.γ phase is the leading phase in eutectic γ+Ni_5Hf and γ bars are surrounded by Ni_5Hf phase.At the section perpendicular or parallel to the γ growing direction,the eutectic morphology is cellular or laminar respectively.The content of Ni_5Hf in the alloy is 68.7v.-%. The compositions of primary and eutectic Ni_5Hf are very similar.Ni,Co and Hf are the main elements and solubility of Cr and W in Ni_5Hf is very low.This alloy is an ideal brazing filler suitable to the directional or single crystal superalloy,and the elements are beneficial to superalloys properties.This filler alloy is of low melting point and of good fluidity.After braz- ing at 1240℃,5 min+1190℃,I h in 10~(-3) Pa vacuum,the microstructure of bond is the same as that of Hf-bearing superalloy.No Si and B contamination is involved.
关键词:
Ni-Hf brazing alloy
,
null
,
null
,
null
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null
