Ni—Fe奥氏体合金的氢脆及成分影响

研究了5种Ni-Fe奥氏体的氢致塑性损失和K_(IC)随成分的变化,发现当Fe含量为60%时,氢致塑性损失极小;Fe为50%时滞后断裂门槛值K_(IH)极小,根据不稳定氢化物含量,固溶氢含量以及位错结构随合金成分的变化解释氢致塑性损失和K_(IH)随成分的变化规律。     

氢对有序态Ni_3Fe合金脆性的影响(英文)

研究了有序态Ni3Fe合金在不同氢气压力中和在不同电流密度电解渗氢时合金的拉伸性能。结果表明：随着氢气压力或电流密度的增加,合金的延伸率先快速下降,随后逐渐趋于恒定;合金的氢脆因子与氢气压力或电流密度之间呈相同的依赖关系。有序态Ni3Fe合金在氢气中的脆化机制是催化反应生成的氢原子进入合金所致,合金的脆化程度与进入合金的氢原子数量有关。     

Effect of atomic ordering on environmental embrittlement of （Co,Fe）3V alloy in gaseous hydrogen

The diffusible hydrogen contents in precharged(Co,Fe)3V alloy were measured.It is found that atomic ordering can not promote hydrogen peretration in the(Co,Fe)3V alloy.The ultimate tensile strength(UTS)and ductilities in various condition were also investigated.The results show that the UTS and elongation of disordered alloy are higher than that of ordered one with fixed diffusible hydrogen content and(Co,Fe)3V alloy with ordered structure is highly sus ceprible to the embrittlement in hydrogen gas.The factor which may affect the susceptibility to the embrittlement of (Co,Fe)3V alloy in hydrogen gas in mainly due to that the atomic ordering may accelerate the kinetics of the catalytic reaction for the dissociation of molecular hydrogen into atomic hydrogen.However,it can not be roled out that atomic ordering intensifies planar slip and restricts cross-slip at the grain boundaries and enhances the suscptibility of the alloy to hydrogen embrittlement.     

硼含量对有序态(Fe,Co)3V合金环境氢脆的影响

通过在真空和氢气环境下的拉伸实验,研究了硼含量对有序态(Fe,Co)_3V合金力学性能和环境氢脆的影响。结果表明,当在有序态(Fe,Co)_3V合金中添加0.02%B(质量分数)时,相对于无硼合金,合金的晶粒尺寸减小了27.5%,合金在真空和氢气中的抗拉强度和延伸率均达到最大值;而当硼含量继续增加时,合金的晶粒尺寸、合金在真空和氢气中的力学性能均保持不变。无硼有序态(Fe,Co)_3V合金在氢气中呈现严重的环境氢脆,当在合金中添加0.02%B后,合金氢脆因子降低了34.4%,合金的断口形貌由完全沿晶断口转变为穿晶和沿晶的混合断口;当合金中的硼含量继续增加时,合金的氢脆因子不再降低,恒定在50%左右,即硼原子只能部分抑制有序态(Fe,Co)_3V合金在氢气中的环境氢脆。     

SURFACE REACTION，HYDROGEN DIFFUSIVITY AND ENVIRONMENTAL EMBRITTLEMENT OF INTERMETALLIC COMPOUNDS Ni_3Al AND Fe_3Al

ＳＵＲＦＡＣＥＲＥＡＣＴＩＯＮ，ＨＹＤＲＯＧＥＮＤＩＦＦＵＳＩＶＩＴＹＡＮＤＥＮＶＩＲＯＮＭＥＮＴＡＬＥＭＢＲＩＴＴＬＥＭＥＮＴＯＦＩＮＴＥＲＭＥＴＡＬＬＩＣＣＯＭＰＯＵＮＤＳＮｉ_３ＡｌＡＮＤＦｅ_３ＡｌＷＡＮＸｉａｏｊｉｎｇ；ＺＨＵＪｉａｈｏｎｇ；...     

Nb—Ti—Ni合金的显微组织与氢渗透性能

研究了Nb50Ti25Ni25及Nb40Ti30Ni30合金的显微组织及氢渗透性能,并与贵金属Pd、Pd-Ag合金及纯Nb的氢渗透性能进行了比较.两种合金的显微组织均由先析出的bcc-Nb(Ti,Ni)固溶体和bcc-Nb(Ti,Ni) B2-TiNi共晶组成.随Ni、Ti合金元素含量增加,合金中共晶相的含量增加.氢渗透温度为673 K时,两种合金的氢渗透系数分别为1.71×10-8和1.03×10-8mol·in-1·s-1·Pa-0.5,接近Pd的氢渗透系数,略低于Pd-Ag合金的氢渗透系数.共晶相的比例增加有利于提高合金的抗氢脆性能,增加先析出相的比例可提高合金的氢渗透系数.适当调整合金元素含量可获得综合性能良好的氢渗透合金.     

（Zr,Ti）（V,Mn,Pd,Ni,Fe）2系贮氢电极合金的循环稳定性

（Ｚｒ，Ｔｉ（Ｖ，Ｍｎ，Ｐｄ，Ｎｉ，Ｆｅ）２系贮氢电极合金具有较高的电化学容量。在充放电循环过程中，发生合金组元有选择地溶了，致使合金Ｃ１４７主相结构严重畸变，逐渐丧失了可逆贮氢能力。     

X80管线钢在含氢煤制气环境中的氢脆敏感性

采用慢应变速率试验和缺口试样拉伸试验,并结合断口分析,研究了X80钢在含氢煤制气环境中的氢脆敏感性。结果表明:高压含氢环境中X80钢的强度和塑性指标均有所下降,断口出现脆断形貌,表现出一定的氢脆敏感性,且横向取样方向对氢脆更为敏感;通过对比分析X80钢在高压氢气环境中慢拉伸和缺口拉伸两种状态下的韧性损失,发现缺口试样的三向应力集中区域受氢脆影响更为严重。     

V合金在聚变堆环境中的使用脆性

利用高温氧化和氢化等方法模拟在聚变堆环境中多种 V-Cr-Ti-Al-Si合金因吸O和H而造成的脆性，并利用国外测试的V合金中子辐照后性能数据， 分析了V合金的中子辐照脆性.V合金在450℃～600℃惰性气体中的高温氧化符合抛物线 规律，除V4Ti3Al合金外，O含量升高使合金的延性降低.H、O联合作用下的V合金表现出了很 强的氢脆敏感性.对含O量为800 μg/g的V4Cr4Ti合金，当H含量超过50 μg/g后表现出明显 的拉伸脆性.中子辐照使V合金的屈服强度升高，而塑性降低，特别是低于400℃的低温中子 辐照，V合金表现出很强的辐照致脆倾向.研究中发现V合金吸氢、中子辐照和形变后的强化 具有等强的降低合金塑性的作用，为此建议采用细晶强化来解决V合金的氢脆和辐照致脆问 题.     

EFFECT OF CHROMIUM AND BORON ON ENVIRONMENTAL EMBRITTLEMENT OF FORGED Fe_3Al

1.IntroductionIronaluminidesbasedonFe3AlandFeAlhaveexcellentresistancetooxidationandrelativelylowcost,whicharepr0misingcandidatesforuseasastructuralmaterialincor-rosiveenvir0nmelltsl1'2].H0wever,thesealloyshaven0tyetfoundwidespreadusebecausetheyexhibitpoorductilityatambienttemperatures,accompaniedbybrittlefracture-Thebrittlebehaviorhasrecentlybeenattributedt0environmenta1embrittlementinvolvinggen-eration0fatomichydr0genatthecracktipwhichisthentransportedintothespecimenduringloadingpr0ducingb…     

A comparison of hydrogen embrittlement susceptibility of two austenitic stainless steel welds

Slow displacement rate tensile tests were carried out to assess the effect of hydrogen embrittlement on notched tensile strength (NTS) and fracture characteristics of AISI 316L and 254 SMO stainless steel (SS) plates and welds. 254 SMO generally exhibited a better resistance to hydrogen embrittlement than 316L. The strain-induced transformation of austenite to martensite in the 316L SS was responsible for the high hydrogen embrittlement susceptibility of the alloy and weld. Sensitized 254 SMO (i.e., heat-treated at 1000 °C/40 min) base plate and weld comprised of dense precipitates along grain boundaries. Interfacial separation along solidified boundaries was observed with the tensile fracture of 254 SMO weld, especially the sensitized one. Dense grain boundary precipitates not only reduced the ductility but also raised the susceptibility to sulfide stress corrosion cracking of the sensitized 254 SMO plate and weld.     

Moisture-induced embrittlement mechanism for (Ni,Fe)Ti alloys

Recent experimental studies showed that the ductility of NiTi is not affected by moisture, while addition of iron beyond 9 a/o in NiTi leads to moisture-induced embrittlement. To explore the nature of this embrittlement, we studied the chemical interaction between water vapor and (Ni,Fe)Ti(110) surfaces with 5 a/o and 10 a/o Fe. Temperature-programmed desorption and X-ray photoelectron spectroscopy show that decomposition of water to produce atomic hydrogen occurs on both surfaces. Activation energy for surface diffusion was calculated by density functional theory, showing that addition of Fe decreases H surface diffusivity, in agreement with experiment. Together with the observation that addition of 9 a/o Fe increases the strength of NiTi, this indicates that moisture-induced embrittlement in higher strength NiTi alloys is not due to faster H surface diffusion, but lower critical hydrogen concentration required for embrittlement.     

氢致TA10钛合金焊接接头拉伸性能演变

钛合金焊接件低氢浓度下常发生氢脆失效,文中研究了充氢量对钛合金焊接接头拉伸性能的影响规律及其作用机制. 结果表明,随充氢量增加,室温强度明显提升,而塑性指标显著恶化. 充氢0.05% (质量分数)时,固溶氢对组织强化效果有限,抗拉强度略有增加;固溶氢降低了溶质原子对位错运动“钉扎”作用,屈服强度下降;固溶氢仅依靠扩散聚集,致局部微区氢浓度增加,其对塑性影响不大. 充氢0.12%后,氢化物“钉扎”作用加强,氢致位错交叉滑移更为困难,室温强度显著增加;脆性氢化物自身断裂、析出特征或加速与基体分离,致塑性显著下降. 未充氢或0.05% H时,焊接接头发生韧性断裂;充氢0.12%后,以脆性断裂为主;固溶氢、氢化物对断裂方式转变产生直接影响.     

Ni2Cr合金室温环境氢脆的研究

对Ni2Cr合金在不同环境气氛及动态渗氢中的脆化进行了系统研究,并从能量学方面分析了影响合金脆化的因素。结果表明,Ni2Cr合金在室温空气及氢气中不存在明显的环境氢脆,动态渗氢拉伸时Ni2Cr合金存在严重的氢脆敏感性,无序和高度有序合金脆化严重,部分有序合金氢脆敏感性较小。     

Moisture and hydrogen-induced embrittlement of iron aluminides

It is now apparent that Fe₃Al and FeAl alloys with less than 40 at.% Al are intrinsically ductile. Brittleness is manifested only in environments providing ready access to hydrogen. Microstructure, alloy content and surface condition may alter somewhat the susceptibility to embrittlement by moisture or by hydrogen, but are key considerations in alloy design for toughness or ductility when aluminum content is within the Fe₃Al-FeAl range. The susceptibility of iron aluminides to moisture and to hydrogen is a major factor hampering their development as structural alloys. Other properties which need to be improved include tensile strength and creep and impact resistance, but approaches to achieve improved strength properties must consider the susceptibility to the external environment. Development of alloys with less than 16% Al appears to be attractive for situations where reduced strength and oxidation resistance can be tolerated because of the insensitivity of these alloys to embrittlement. However, it must be realized that these alloys are not intermetallics.     

The effect of copper content and heat treatment on the hydrogen embrittlement of 7050-type alloys

The effect of copper content (0.01 and 2.1%) and microstructure on the intrinsic hydrogen embrittlement susceptibility of unl nercially-processed AI---6Zn---2Mg---XCu alloys was investigated. (The alloy with 2.1 Cu corresponds to 7059). Hydrogen was introduced into the alloys using cathodic charging, both with and without concurrent plastic straining. The copper-free alloy in both the under-aged and peak-aged conditions was embrittled by hydrogen and the effect was enhanced by concurrent plastic strain. The copper-containing alloy (7050) was susceptible to hydrogen embrittlement when under-aged, but once the peak-strength microstructure had been developed, the alloy in the longitudinal direction showed no embrittlement even under severe hydrogen-entry conditions. Similar beneficial effects have been reported for copper additions in imparting resistance to humid air and stress-corrosion cracking for high strength AI-Zn-Mg alloys, and the results are discussed with emphasis on the parallel nature of the phenomena of stress-corrosion cracking and hydrogen embrittlement.     

Co含量对FeCoPB非晶合金软磁性能和弯曲韧性的影响

采用熔体旋淬的方法制备了Fe Co含量达到87 at%Fe-Co-P-B系非晶合金薄带,研究了金属元素Co对Fe-Co-P-B系非晶合金的形成能力、软磁性能和弯曲韧性的影响规律。该合金系具有高的饱和磁化强度1.75～1.84 T,且热处理后薄带仍具有良好的弯曲韧性。添加Co元素后,提高了合金的居里温度,矫顽力升高。对薄带样品施加12 MPa的拉应力,合金的矫顽力由12.8 A/m降低到6.5 A/m。因此,通过成分和应力的调控可以避免Fe基非晶合金热处理引起的弛豫脆性问题,为获得具有优异软磁性能和良好弯曲韧性的Fe基非晶合金提供重要途径。     

非晶态Fe－B－Si合金的退火脆化

非晶态Ｆｅ－Ｂ－Ｓｉ合金的退火脆化具有明显的成分依赖性，并且对制备条件和退火方式比较敏感；近共晶成分的合金（如Ｆｅ８０Ｂ１１．５Ｓｉ８．５和Ｆｅ７９Ｂ１１．５Ｓｉ９．５等）和适当液淬工艺条件下制备的非晶合金薄带具有相对较小的脆化倾向。与常规退火工艺相比，脉冲电流加热快速退火，可在保持延性基本不变的情况下，明显改善合金的磁性；是获得非晶态Ｆｅ－Ｂ－Ｓｉ合金磁性优化与良好延性配合的有效途径之一     

Ab initio study on plane defects in zirconium–hydrogen solid solution and zirconium hydride

Hydrogen embrittlement of zirconium alloys is one of the main causes of the mechanical degradation of the fuel cladding in light water reactors, and has therefore been extensively studied. Although various conjectures have been proposed as the origin of such embrittlement, it is not known which one plays the most important role: the brittle nature of the hydride, micro-crack nucleation by interaction of hydride precipitates with dislocations or void nucleation at the interface between hydride precipitates and zirconium matrix. The purpose of the present study was to elucidate the origin of the embrittlement by investigating the fracture properties of the hydride. We have evaluated the surface energy γ_S and unstable stacking energy γ_US of Zr–H systems by using ab initio calculations. The ductile/brittle behavior of the hydride is discussed based on the difference between γ_S and γ_US among the hydride, pure zirconium and hydrogen solid solution. For the solid solution at a H/Zr ratio less than 0.5 we obtained a monotonous decrease by 15–34% and 50–100% in γ_S and γ_US, respectively, from those in pure zirconium, indicating a reduction in both brittleness and ductility. Thus, hydrogen-induced embrittlement of the hcp Zr matrix was not confirmed. On the other hand, for the hydride we obtained a 25% smaller γ_S and a 200–300% larger γ_US than those in pure zirconium. This indicates that zirconium hydride has an extremely brittle nature due to the synergistic effect of a small γ_S, implying easy generation of a fracture surface, and large γ_US, implying a difficulty in dislocation motion, compared with pure zirconium. Furthermore, Rice’s ductile/brittle parameter D was 1.4 in the δ-hydride, indicating that it undergoes brittle fracture more easily than iridium, known as an extremely brittle material. These results seem sufficient to attribute hydrogen embrittlement of zirconium alloys substantially to the brittle nature of the hydride.     

回火温度对DP600钢氢扩散及氢脆敏感性的影响

利用慢应变速率拉伸和双电解池氢渗透试验,结合SEM、TEM、EBSD表征手段研究了不同回火温度下DP600钢中显微组织变化对其氢扩散及氢脆敏感性的影响。结果表明,DP600钢的氢脆敏感性和有效氢扩散系数均随回火温度的升高呈下降趋势,这主要与钢中位错、小角度晶界等可逆氢陷阱浓度降低以及碳化物/基体界面、大角度晶界等不可逆氢陷阱浓度增加有关。其中弥散分布的碳化物使碳化物/基体界面捕获的氢原子分布均匀,导致试验钢的氢脆敏感指数由44.6%(270 ℃)下降至1.8%(350 ℃)。综合考虑回火温度对试验钢强度和氢脆敏感性的影响,DP600钢的最佳回火温度为330 ℃。