共查询到19条相似文献,搜索用时 46 毫秒
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单晶镍基高温合金的蠕变断裂 总被引:1,自引:0,他引:1
本文研究了〈001〉取向的CMSX—2,SRR99和RR2000三种单晶镍基高温合金,从750-1000℃温度范围和从150—680MPa应力下的蠕变断裂特征;用扫描电镜对上述各种实验状态下的蠕变断口和纵向剖面进行了详细观察。结果表明:单晶的蠕变断裂具有明显的晶体学特征,蠕变裂纹总是从已有的铸造的显微疏松处萌生;对于含碳量较高的材料,碳化物及其与基体的界面也是裂纹萌生的有利位置;这些已萌生的裂纹在外加应力轴垂直的(001)面上各向异性地扩展,直到由于承载截面的逐渐减小而导致最终破坏。虽然在较高的实验温度下,断口被强烈地氧化,但是蠕变断裂特征没有改变,在对三种材料断口上(001)面的大小和面积分数的测量和计算表明,用面积分数来表征蠕变损伤程度是可行的。 相似文献
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DD3单晶高温合金的高温蠕变断裂行为 总被引:3,自引:1,他引:3
通过对DD3单晶高温合金试棒进行1030℃/196MPa、1040℃/177MPa和1050℃/140MPa蠕变实验,并对试样断口形貌及其组织进行观察和分析,研究了第一代单晶高温合金DD3的高温蠕变断裂行为。蠕变试验结果表明:在1030~1050℃条件下,DD3合金具有优良的蠕变性能;蠕变开始不到10h,合金即进入稳态蠕变阶段。断口形貌及组织分析表明:高温条件下的DD3单晶高温合金蠕变断裂裂纹萌生于微孔,断裂模式为微孔聚集型断裂。 相似文献
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研究了不同热处理状态的ZL107合金在107℃的高温静态蠕变和循环蠕变的行为。结果发现:峰时效下,合金的蠕变抗力强于过时效状态下材料的蠕变抗力。 循环蠕变时材料表现出蠕变减速现象。经峰时效处理的ZL107合金在循环蠕变中表现出较静态蠕变低的激活能,用非热空位机制进行了解释,而经过时效处理的ZL107合金表现出高的激活能,滞弹性机制起了重要作用。 相似文献
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用人工神经网络法预测镍基单晶高温合金的蠕变断裂寿命 总被引:4,自引:0,他引:4
根据大量镍基单晶高温合金在不同温度和应力下的蠕变断裂寿命数据,采用一种先进的人工神经网络方法建立运算模型,对合金在不同实验或运行条件下的蠕变断裂寿命进行了预测,并将测算结果与现有其它方法进行了比较.结果表明,所建网络能较准确预测第一、二、三代镍基单晶合金的蠕变断裂寿命.将正交试验分析与网络预测相结合,获得在982℃/250MPa下给定合金成分范围的各元素对其蠕变断裂寿命影响程度的排序. 相似文献
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张源虎 《腐蚀科学与防护技术》1995,7(2):108-114
研究了分别为轧制、普通铸造、定向凝固及单晶的6种高温合金在热腐蚀条件下的蠕变断裂性能.其中涉及到试验温度、晶粒尺寸、晶界状态等对性能的影响.探讨了蠕变应变与热腐蚀交互作用下,合金中所产生的灾害性侵蚀及断裂过程. 相似文献
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ZHANG Yuanhu SUN Jian XIANG Yi HU Gengxiang Shanghai Jiaotong University Shanghai ChinaLI Tiefan Institute of Corrosion Protection of Metals Academia Sinica Shenyang China Yuanhu Department of Materials Science Engineering Shanghai Jiaotong University Shanghai 《金属学报(英文版)》1991,4(2):118-122
Studies on the high temperature creep and fracture behaviours in air or in SO_2 contaminatedenvironment for the Fe-base superalloy GH302 with flat or zigzag grain boundaries(GB)and the Ni-base superalloy Rene 80 were carried out.Although the creep rupture propertiesof the GH302 with zigzag GB was remarkably superior to that of flat GB in air,the propertiesof both droped dramatically in 10% SO_2-air environment,the creep rupture properties of thedirectional solidified Rene 80 were much better than that of the conventionally cast alloy inair,and also kept the same property in SO_2 contaminated environment as in air.Owing to theinteraction between creep and sulphidation,the failure mechanism relates to the formation ofmolten Ni-Ni-3S_2 eutectic along GB,led to the premature failure of the alloy. 相似文献
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1.IntroductionTheevolutionofsuperalloyshasbeengreatlymotiVatedbythedevelopmentofmodernjetengines.Somepartsoftheengineareoperatedathightemperaturesandsubjectedtobothstaticanddynamicforcesaswellasthermalgradients.Therefore,creepcanoccuratsignificantratesandthentheestimationofcreepstrainandtheassociateddamageaccumulationbecomethecriticalconsiderationinthedesignoftheenginebladesoperatingathightemperatures.ThepurposeofthisinvestigationwastoexaminethecreeppropertyandfracturebehaviorofthecastK417and… 相似文献
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ZHANG Junshan CHEN Weixing CAO Zhiben Dalian University of Technology Dalian China Associate Professor Department of Materials Engineering Dalian University of Technology Dalian China 《金属学报(英文版)》1989,2(5):368-373
Creep behavior of Fe-15Cr-25Ni alloys with different grain boundary features has been in-vestigated at 850 and 950℃ and in stress range of 14.7~78.5 MPa.The single phase alloyexhibits typical recovery creep characteristics,and for the alloy in which M_(23)C_6 carbidesdensely precipitate at grain boundaries,the creep rate dramatically decreases and creep behav-ior is also significantly different from the single phase alloy.When the carbides precipitate atgrain boundaries,the dislocation density are higher and the size of subgrains near grainboundaries are smaller than those of single phase alloy.The creep mechanisms for two grainboundary features have been discussed. 相似文献
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铸造镍基高温合金的蠕变阻力 总被引:6,自引:0,他引:6
在对颗粒强化理论和位错蠕变理论进行回顾、评价基础上,发展了一个位错蠕变阻力模型,认为蠕变阻力是影响铸造镍基高温合金蠕变机制的重要因素。当施加应力足以使位错切入γ′相时,主要蠕变机制是位错切割γ′相过程,蠕变阻力就是位错切入γ′相的临界门槛应力。在低施加应力区,位错只能借助于热激活攀移过程通过γ′相。蠕变阻力包括两部分:第一项是位错攀移临界门槛应力,与施加应力无关;第二项是与施加应力有关的阻力项,代表了其他强化机制的贡献。位错攀移机制蠕变阻力的上限是切割机制门槛应力。在3种铸造镍基高温合金中(定向凝固DZ17G合金,IN100合金和IN738合金),对上述模型进行了验证,理论计算应用了SL强化理论,与实测值符合较好。 相似文献
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MA Peili YUAN Ying ZHONG Zengyong Central Iron Steel Research Institute Ministry of Metallurgical Industry Beijing China MA Peili Senior Engineer Lab.of Superalloy Central Iron Steel Research Institute Ministry of Metallurgical Industry Beijing China 《金属学报(英文版)》1990,3(3):208-212
By adding small amount of Mg to the wrought superalloys,the steady stage of creep,and es-pecially the tertiary stage of creep are prolonged.Also,the steady creep rate is decreasedwithin the range of low strain rates.At higher strain rates,however,the effect of Mg on creeprate vanishes.This may be attributed to the Mg dissolution in the matrix.A mechanism of theeffects of Mg addition on creep behaviors is proposed. 相似文献