共查询到20条相似文献,搜索用时 15 毫秒
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ZHU Qiang GE Honglin WANG Di CHEN Guoliang University of Science Technology Beijing Beijing China.Originally published in ACTA METALL SIN 《金属学报(英文版)》1989,2(6):408-411
The segregation of Mg to phase interfaces in a nickel base superalloy IN 100 has been investi-gated using EPT(Electron Microprobe Technique).AES(Auger Electron Spectroscopy)and EDS analyses on thin TEM film.The results show that Mg segregates to the phase inter-faces of MC/γ and γ′/γ.The segregation concentration and layer thickness of Mg onMC/γ phase interface are larger than that on γ′/γ phase interface.Mg is not only a grainboundary segregation element,but also a phase interface segregation one. 相似文献
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研究了镍基高温合金Ni-10Cr-15Co-6W-6Mo-4Al-2Ti真空电弧重熔过程中自耗电极熔化特征及电极端部不同区域内Mg的分布。发现在电极侧表面存在着一个重熔金属环,Mg在其中分布相当均匀,而在重熔金属液层及液固两相区内Mg分布则不均匀。金属液层厚度随其在电极端部所处位置而异,其平均值为1—1.5mm。分析结果指出,Mg含量从金属液层/气相界面经液固两相区至原始电极区即随距金属液层/气相界面距离δ_1增加而增加。重熔金属环中Mg含量[Mg]_r及熔化金属液外层(δ_1<0.40mm)中Mg含量均低于重熔锭中Mg含量[Mg]_i。在试验条件下,如自耗电极Mg含量以[Mg]_e代表,则[Mg]_(0.15)=0.18[Mg]_e=[Mg]_r;[Mg]_(0.40)=0.30[Mg]_e=[Mg]_i。真空电弧重熔过程中,Mg挥发主要发生于电极端部熔滴形成阶段,流经电极端面的金属液不能全部暴露于真空下,Mg挥发过程受控于Mg原子由原始电极区向金属液层/气相界面迁移的速度。传质系数K_(12)=0.107cm·s~(-1)。重熔锭中Mg含量[Mg]_i=[Mg]_e exp(-K_(12)·A·γ·W~(-1))。显然,可通过控制电极Mg含量[Mg]_e及熔化速率W来实现最佳Mg控制。 相似文献
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研究了Ni基高温合金Ni-10Cr-15Co-6W-6Mo-4Al-2Ti真空熔炼过程中Mg挥发动力学。结果表明,真空感应熔炼过程中,当炉内Ar压力保持在100—400mmHg时,合金中Mg挥发速率受Mg在液相边界层中扩散及金属熔池/气相界面挥发反应双重控制,而非受控于气相边界层中Mg的扩散。双重控制时Mg的传质系数为10~(-5)—10~(-2)cm·s~(-2)数量级,而气相边界层中Mg的传质系数为140cm·s~(-1)左右。借助于动力学公式、回归方程及特殊的参数转换,建立了一个简单的Mg挥发数学模型,该模型计算结果与实验室及生产条件下试验数据很好地符合,因此,可通过控制熔炼参数,例如向金属熔池加Mg量,Ar压力,挥发温度及时间等来精确地控制最佳Mg含量。 相似文献
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在高温镍基变形合金中,加入微量Mg元素,可使晶界中的连续条状碳化物变成不连续的块状,从而提高了蠕变应力指数n;并降低晶界扩散系数,提高其蠕变激活能;使晶界能和碳化物-基体的相界能降低,提高了界面结合力。这些因素抑制了晶界滑动,阻止了裂纹的产生和扩展,显著地改善了合金的蠕变性能和持久寿命。 相似文献
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一种镍基高温合金的碳化物析出与转化动力学 总被引:2,自引:0,他引:2
采用化学分离联合衍射定量分析法,对多相镍基合金进行了定量相分析研究,得到了850—1000℃下MC的分解和M_(23)C_6,M_6C的析出与热暴露时间的双曲线型变化规律。热暴露过程中M_(23)C_6的元素组成一直在变化,刚析出时为(Cr_(0.67)Mo_(0.13)Ni_(0.13)Co_(0.07))_(23)C_6,其后Cr量增高,Mo,Ni和Co量减少,最终组成为(Cr_(0.88)Mo_(0.07)Ni_(0.03)Co_(0.02))_(23)C_6。热暴露温度愈高,M_(23)C_6达到最终组成状态愈快。 相似文献
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HUANG Qianyao SHI Yanyu Central Iron Steel Research Institute Ministry of Metallurgical Industry Beijing China Department No. Central Iron Steel Research Institute Ministry of Metallurgical Industry Beijing China 《金属学报(英文版)》1989,2(3):181-185
The quantitative analytical method combining the electrolytic extraction with X-raydiffraction analysis to determine the carbides and TCP in a Ni-base superalloy wasdeveloped.The variation of decomposition of MC and precipitation of M_(23)C_6 and M_6C withhot 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 primarystage 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 beachieved. 相似文献
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少量Mg和Zr对一种Ni-Cr-Ti型变形合金蠕变裂纹长大行为的影响 总被引:1,自引:0,他引:1
采用电位法测定单边切口试样700℃下的蠕变裂纹生长,并测定裂纹起始寿命和断裂寿命(t_(rc)和t_r)。用能量率积分(C~*)描述稳态蠕变条件下裂纹顶端附近的场。给出裂纹长大速率与C~*的函数关系,预报的裂纹起始时间与实测值相符。发现合金中加入少量Mg和Zr可以大大延长蠕变裂纹起始寿命和蠕变断裂寿命。 相似文献
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GUO Encai XU Fengqin Central Iron Steel Research Institute Ministry of Metallurgical Industry Beijing China GUO Encai Dept.No. Central Iron Steel Research Institute Ministry of Metallurgical Industry Beijing China 《金属学报(英文版)》1989,2(2):147-152
The creep crack growth(CCG)and the time to carck initiation and rupture of specimen(t_(rc)and t_r)were measured by means of electrical potential method on single edge notchedspecimens at 700℃.The field near the crack tip under steady-state creep was represented byenergy rate integral(C~*),and the CCG rate as a function of C~* has been obtained.Theagreement between the predicted and observed t_(rc)values is quite good.It was found that theaddition of small amount of Mg and Zr in the alloys causes t_(rc)and t_r of the specimens to in-crease significantly. 相似文献
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本文研究了Ni基高温合金电渣重熔CaF_2-MgO-Al_2O_3-CaO-0.5mol%TiO_2渣系成分对合金中Mg,Al,Ti含量的影响规律。当渣池温度为1690±10℃时,在0.10≤N_(MgO)≤0.25,0.05≤N_(Al_2O_3)≤0.21,0.05≤N_(CaO)≤0.15范围,建立了以下函数关系。 [Mg]=0.881[Al]_0~(0.641)N_(MgO)~(4.114-2.835N_(CaO)+1.077InN_(Al_2O_3))N_(Al_2O_3)~(1.282),wt-% [Al]=[Al]_0-(0.19+0.804N_(CaO)~(0.454)-1.70N_(Al_2O_3))vA/45.36V,wt-% [Ti]与N_(MgO),N_(Al_2O_3)变化无关,它随N_(CaO)增加而略增。 相似文献
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HU Benfu LI Huiying WU Chengjian ZHANG Shouhua University of Science Technology Beijing Beijing China Associate Professor Dept.of Material Science Engineering University of Science technology Beijing Beijing China. 《金属学报(英文版)》1991,4(2):97-102
The solidification microstructure and phase composition of Ni-base superalloy FGH95 pow- der with different mesh size have been investigated.The structure transition was found from dendrite in major into cellular structure as the powder size reduces and the cooling rate in- creases.The predominant phase was identified as MC-type carbide,with different morphologies,which may be related to their composition and the condition of solidification.Minor phases,such as boride,Laves and primary γ' are also present as ac- companiments of the carbide. 相似文献
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在12%(NH_4)_2SO_4水溶液(调pH=9)中,电位在200—800mV(SCE)范围内实现了M_(17)G镍基高温合金中M_(23)C_6相的选择性阳极浸蚀。用线性扫描电位法和恒电位阶跃法研究了浸蚀过程,建立了电化学极化控制下细小、弥散相的选择性阳极浸蚀过程模型。 相似文献
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SUN Liling DONG Lianke ZHANG Jishan TANG Yajun ZHANG Jinghua HU Zhuangqi Institute of Metal Research Academia Sinica Shenyang China SUN Liling Institute of Metal Research Academia Sinica Shenyang China 《金属学报(英文版)》1993,6(5):291-295
The morphology of solid/liquid interface of a directionally solidification process is describedby means of fractal analysis,and the relations among the fractal dimension of the solid/liq-uid interface,solidification rate,dendrite arm space and the phosphorus content of the test al-loys have been given.It was found that the increase of the solidification rate and the phos-phorus content of the test alloy will lead to a increase,following the regularity of exponentialfunction,in the fractal dimension of solid/liquid interface.Furthermore,by combining thefractal theory and the thermodynamic principle with the measured results,it has been provedthat the fractal dimension is not only a kind of simple geometrical parameter used in des-cribing irregular geometry,but also a state function depending the change of solidificationparameters and chemical compositions. 相似文献
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镍基铸造高温合金的热等静压处理 总被引:3,自引:0,他引:3
评述了镍基铸造高温合金的热等静压(HIP)处理对组织和力学性能的影响。镍基铸造高温合金由于存在着铸造工艺难以消除的气孔类缺陷,严重影响着合金的使用可靠性和成品率,通过HIP处理后的合金,不仅可有效地消除合金中的缺陷,获得致密合金,而且还可改善合金的显微组织,提高合金的拉伸、持久和疲劳性能,显著地减小性能分散度。 相似文献