共查询到13条相似文献,搜索用时 62 毫秒
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含Ru铸造镍基高温合金的显微组织 总被引:2,自引:0,他引:2
研究了3%(质量分数)Ru对低Cr高W铸造镍基高温合金的影响。对比分析了含Ru和无Ru合金的铸态,1260℃/4h,1260℃/4h 1280℃/4h,1260℃/4h 1300℃/4h固溶热处理和1260℃/4h, 1100℃/100h热暴露试验得到的显微组织。结果表明:Ru的加入不会改变合金中析出相的种类,但会影响γ'相和M6C碳化物的稳定性,使γ'的固溶温度大约降低10℃,并使合金在1100℃下有较强的γ'筏排化倾向。Ru明显抑制合金中初生和次生M6C碳化物的析出,有利于稳定高温合金的显微组织。 相似文献
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采用无机盐料浆法在K4104镍基高温合金表面制备Al-Si涂层。依据GB/T13303-91《钢的抗氧化性能测定方法》标准,采用静态增重法对有涂层试样和无涂层试样进行了1000℃×200h抗高温氧化性能试验,并绘制了氧化动力学曲线。用带能谱扫描电镜对氧化膜的表面形貌和截面组织进行分析,研究有无涂层试样在高温氧化过程中的元素扩散。结果表明:Al-Si涂层和基体合金之间在高温氧化过程中的互扩散形成了厚度为120~140um的渗层。随着氧化时间的延长,外层铝含量逐渐降低,但仍能保持稳定的β-NiAl相。Si在扩散作用下形成内高外低的分布形式,形成的Cr3Si和富Si的M6C相有利于阻止涂层和基体元素之间的互扩散,降低化合物层的形成速度,体现了Al-Si涂层良好的抗高温氧化能力。 相似文献
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K465镍基高温合金为母材,FGH95镍基合金粉为预填粉末,采用预填高熔点粉末的方法对0.5mm大间隙接头进行钎焊,研究不同保温时间对钎缝组织与接头性能的影响。结果表明:1220℃保温0.5h获得的钎缝组织由合金粉颗粒及颗粒间的相构成,颗粒内为γ和γ′两相组织,颗粒间为γ和γ′两相为基体的硼化物、硅化物及γ+γ′共晶组织;随钎焊保温时间延长,合金粉颗粒长大,化合物相及γ+γ′共晶组织合并、总量减少;钎焊保温时间为0.5~16h时,接头平均持久寿命由31.59h提高至54.58h,但不易获得高性能等温凝固接头。 相似文献
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在对IN738LC合金的含保载低周疲劳试验中发现,蠕变变形的增加导致了疲劳寿命的降低,在对试样的微观检验中未见有典型晶界孔洞型蠕变损伤,而多见的碳化物及晶界的氧化,所有的裂纹都在试样表面萌生并沿着扩展,因此,在蠕变载荷下晶界氧化是一种可能的蠕变损伤,这里运用Danzer关系讨论了损伤的机理,并对实验结果进行了较理想的解释。 相似文献
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喷射成形镍基高温合金的研究进展 总被引:6,自引:0,他引:6
喷射成形是一种新型快速凝固技术,采用这项技术制备的镍基合金,具有细小,球状的晶粒和均一的组织,从而提高其性能,综述了喷射成形镍基高温合金的发展概况及组织,性能特点。 相似文献
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镍基单晶高温合金的再结晶 总被引:1,自引:0,他引:1
镍基单晶高温合金作为先进发动机叶片的主要用材,其再结晶问题日益受到重视.本文综述了热处理温度、热处理时间、变形程度及合金成分等多种因素对镍基单晶高温合金再结晶的影响规律,分析了镍基单晶高温合金再结晶对其蠕变和疲劳性能的影响,并讨论了回复处理及浸蚀直接去除表面变形层、渗碳和表面涂层等控制再结晶的方法.最后,指出了镍基单晶... 相似文献
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《Virtual and Physical Prototyping》2013,8(3):293-306
ABSTRACTMetal inert gas (MIG), Tungsten INERT GAs (TIG), laser and Electron beam (EB) cladding processes are used in cladding-based Additive manufacturing (AM). Only in the case of MIG, the raw-stock is fed axially into the molten pool resulting in the omni-directional cladding. In other processes, the raw-stock is fed off-axially into the molten pool resulting in deviation in the bead geometry from its actual trajectory and varying bead cross-section along the path. As the trajectories vary widely in cladding-based AM, it is required to maintain a consistent raw-stock feeding condition (namely, front, back or sides). Therefore, an auxiliary wire orienting mechanism has been developed which can be easily retrofitted with a conventional TIG cladding torch and CNC machine. The wire orientation angle is computed on-the-fly and hence the NC programme need not provide this information. Although this implementation was demonstrated for TIG, the same methodology holds good for laser and EB too. 相似文献
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Xiao Huang N. L. Richards M. C. Chaturvedi 《Materials and Manufacturing Processes》2004,19(2):285-311
Electron beam welding was conducted on cast alloy 718 with varying grain sizes obtained using Microcast (MX™) and conventional cast (CC) techniques. The average value per section of Total Crack Length (Av. TCL) was measured on each cross section and used to represent the material's weldability. It was found for the first time that the grain size had a reduced effect on the weldability of cast alloys, relative to that reported in the literature for wrought alloys; i.e., increased grain size in the range of 90-3000 microns resulted in improved weldability. This was determined to be related to the probability of welds intersecting grain boundaries and causing grain boundary microfissuring. The conclusion from the experimental analysis is corroborated by the use of a Weibull-type analysis to evaluate the probability of a weld microfissure occurring relative to the grain size. As grain size increases, the probability of the weld intersecting the grains is reduced, and thus, the likelihood of microfissuring is reduced. With regard to a single crystal, there are no grain boundaries intercepting the weld (probability = 0), and thus, microfissuring related to constitutional liquation of primary carbides, or segregation of species to grain boundaries would not occur. 相似文献
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薄壁管材热态内压成形时,管材内部各处受到均匀内压的作用,但是由于管材各处的温度和边界条件不同,所以将产生复杂的变形过程。讨论热态内压成形时影响管材变形的主要因素,揭示管材热态内压成形时产生不均匀变形的主要原因。在此基础上,结合实例说明如何从控制温度分布和模具约束条件2个方面来控制管材的变形。采用不均匀温度分布,可改变各区域材料的变形抗力和摩擦状况,提高管材零件的壁厚均匀性;采用局部快速加热,可实现长管状零件的局部成形而无需大尺寸的模具;采用局部模具约束,可改变不同区域变形的先后顺序、有效控制变形的不均匀性,从而提高管材的成形性能。 相似文献