共查询到19条相似文献,搜索用时 46 毫秒
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在电化学渗透法测量65Mn钢五种显微组织陷阱参数的基础上,用陷阱参数分离法得到下贝氏体中位错的陷阱能为28.1KJ/mol;回火马氏体中孪晶应变场的陷阱能力74.4KJ/mol;挛晶和位错作为混合陷阱的陷阱能力49.6KJ/mol. 相似文献
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报道了超高真空气相氢渗透实验装置的设计及研制。用溅射离子泵获得超高真空,监测室本底真空度为6×10~(-7)Pa。用圆弧刀口银垫片活密封方式对试样进行密封,实验的极限温度可达650℃。采用B-A规对渗透氢流所引起的压强变化进行动态监测,再通过标准漏孔对系统进行标定,从而定量监测氢渗透动力学过程。采用本实验装置,准确地测量了HR-1型奥氏体不锈钢的氢渗透热力学参数。 相似文献
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用电化学渗透法分别研究了65Mn钢五种不同组织对氢扩散系数和陷阱能的影响,结果表明,珠光体,球化珠光体,回火索氏体,下贝氏体,回火马氏体的陷阱能分别为16.71、30.32、31.35、31.01、35.61(KJ/mol)。 相似文献
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用电化学渗透法研究了交变周次对65Mn钢三种组织珠光体、球化珠光体回火索氏体的氢扩散系数和陷阱参数的影响。 相似文献
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氢在钢中晶格间隙和氢陷阱之间的扩散模式 总被引:1,自引:0,他引:1
氢在晶格间隙和陷阱点的扩散包括:氢在晶格间隙之间的扩散,氢从晶格间隙扩散到陷阱点,氢从陷阱点逃逸到晶格间隙的过程。本文运用气体在金属中的扩散理论,分析了氢在钢中晶格间隙和氢陷阱之间的扩散模式,以及通过扩散在两者之间建立的平衡状态。氢陷阱中氢浓度随时间的变化率等于晶格间隙的氢扩散到陷阱点引起的氢浓度变化率减去陷阱点中氢逃逸到晶格间隙引起的氢浓度变化率,其数学关系式符合McNabb和Foster建立的氢陷阱模型。氢在晶格间隙和陷阱点之间的平衡,实质是氢在晶格间隙的化学势μL和氢在陷阱点的化学势μT之间达到局部平衡,氢在陷阱中的占据分数很低的情况下(θT《1),氢的有效扩散系数Deff的表达式是与陷阱结合能EB有关的温度函数。 相似文献
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An important structural component of the Westinghouse Large Coil Programme superconducting magnet is the JBK-75 (modified A-286) stainless steel conductor sheath. Because the presence of pre-existing cracks or flaws in the conductor sheath is a potential possibility, the structural reliability of the conductor sheath would be enhanced if a threshold level of stress intensity range (ΔKth) was established below which fatigue crack growth would not occur. Consequently, near-threshold fatigue growth rate data were generated at two load ratios on JBK-75 stainless steel at room and cryogenic temperatures. No load ratio effect on near-threshold fatigue crack growth rate was observed at cryogenic temperatures. 相似文献
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M.D. McMurtrey D.E. Mills J.T. Burns 《Fatigue & Fracture of Engineering Materials & Structures》2019,42(1):3-18
UNS S17400 steel is used in turbines for the aerospace and utility industries. While it is generally corrosion resistant, it is susceptible to pitting when exposed to aqueous chloride environments. Effects of pitting characteristics, such as depth, width, and local density on fatigue life, have been studied in this work to better inform criteria for component replacement or repair. While pit depth correlates well with cracking, the deepest pit never initiated the crack that ultimately led to failure. The clustering of pits, or local pitting density, also correlated well with crack initiation location; however, the densest region of pitting was not always the location where cracking occurred. There is likely no single metric that directly correlates pitting with fatigue cracking, rather there is a combination of pitting characteristics that ultimately lead to cracking. The results from this work suggest that pit depth and local pitting density are among the more important metrics. 相似文献
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在316L不锈钢上采用金属有机化学气相沉积(MOCVD)法沉积了氧化铝涂层。使用XRD、SEM分析氧化铝涂层的物相和微观形貌, 采用气相氢渗透装置对涂层氢渗透行为进行表征。结果表明, 973 K退火处理后涂层为非晶氧化铝, 涂层均匀、完整, 厚度为190 nm。氧化铝涂层的氢渗透压力指数为0.56~0.78, 说明氢渗透过程机制为表面过程和体扩散过程共同控制。氧化铝涂层的表观氢渗透率为P = 1.99×10-6 exp(-117×103/RT) mol/(m·s·Pa1/2)。氧化铝涂层的氢渗透激活能为117 kJ/mol, 远高于316L不锈钢的66.6 kJ/mol, 涂层对氢的渗透具有明显的阻挡作用。此外, 在873~973 K氧化铝涂层对316L不锈钢的氢渗透阻挡因子(PRF)为59~119, 涂层氢渗透阻挡性能优异。 相似文献
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本文对各种加热温度及冷却速度下的由第一汽车厂和大连钢厂联合开发,研制的35VS非调质易切钢的组织和性能进行了研究,结果完明,珠光体体积百分数和冷却速度有关,但奥氏体晶粒尺寸随着加热温度升高而增加,并在1050℃时发生突然长大,珠光体片层间距随冷却速度的增加而减少,铁素体的显微硬度明显高于35钢中铁素体的硬度。室温强度指标σb6和σ0:2随加热温度的升高而增加,室温塑性指标和δ随加热温度升高而降低,在性能和冷却速度关系曲线中,当冷却速度为60℃/min时,35VS钢具有较好的塑性,这种冷却速度下得到的组织呈魏氏组织。 相似文献
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A new model of hydrogen diffusion in metalshas been developed,it is more efficient todescribe the hydrogen diffusion with trappingin metals.In the model newly developed an impli-cit dependence on time of hydrogen diffusioncoefficient in metals with trapping was firstlybuilt and it is shown that hydrogen diffusioncoefficient will be different at different posi-tions in a dynamic process of hydrogen diffusionin a metal.Numerical solutions of the present modelwere obtained by finite difference method.Bychanging the parameters in the model the diffusionof hydrogen in a metal and the effect of trappingwere described and discussed.And the comparisonbetween the well known McNabb and Foster's modeland the present model was also made. 相似文献
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采用热喷涂及激光重熔表面改性处理技术,研究了奥氏体不锈钢表面纯铝激光重熔涂层抑制氢渗透的性能及其组织,结果表明涂层具有一定的抑制氢渗透的能力,其原因与涂层的性能和微观组织密切相关。 相似文献