共查询到20条相似文献,搜索用时 15 毫秒
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采用交流阻抗、恒电流集气等电化学方法对比了含与不含混合稀土铝合金在4 mol/L KOH溶液中的阳极行为,并结合金相显微镜、电子探针等表面分析技术探讨了混合稀土元素对铝阳极性能的影响.结果表明:稀土使铝阳极的晶粒细化,阴极相减少,溶解均匀性增强,自腐蚀析氢量减少,性能得到优化. 相似文献
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ZHOU Zhao JI Shichen HU Zhuangqi SHI Changxu 《金属学报(英文版)》1989,2(2):137-142
Study of the solidification process of both Al-Si and Al-Cu alloys proved the presence ofacoustic emission phenomena.Two peaks of count rate have been observed.The total countsof both peaks increase with the increasing hydrogen content of the alloy.The mechanism ofproducing the acoustic emission has been discussed.At the same time,results obtained by oth-er techniques strongly support the good correlation between the acoustic emission andhydrogen releasing during solidification.The bubble nucleation between dendrite arms is themain cause of the first peak,while the fracture of the bridge connecting the interdendrites atthe later stage of solidification is the main cause of the second peak.It is probably due to thehydrogen evolution and accumulation to create high pressure in the interdendritie region. 相似文献
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不同铝添加量对镁合金显微组织及大气腐蚀行为的影响 总被引:1,自引:0,他引:1
利用SEM、EDAX、XRD等技术分析3种不同Al添加量的镁合金的显微组织和相结构,经实验室模拟金属大气腐蚀实验后观察其腐蚀形貌。结果表明,随着Al含量的增加,Mg-Al合金中β相(Mg17Al12)的数量明显增加;不存在β相的镁合金表面腐蚀产物较少,基体腐蚀较浅,存在β相的镁合金表面腐蚀产物较多,基体出现较深的腐蚀坑;β相的数量与分布的不同是镁合金腐蚀形貌存在差异的主要原因。 相似文献
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Al-Li合金定向凝固的热溶质对流 总被引:3,自引:0,他引:3
研究了亚共晶二元Al-Li合金垂直向上定向凝固期间热溶质对流共晶生长的影响,结果表明,晶体生长初期,对流对共晶生长影响较小,能够获得规则的共晶组织,当存在非稳定性对流时,在生长方向上,β相(AlLi)呈非连续的短棒结构;在水平方向上,β相呈波形排列,并且还发现,非稳定性对流中存在着最不稳定波,且这种波对共晶生长上的影响最强烈,它使共晶组织粗大,并且迎着流体流动方向生长。 相似文献
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YIN Weimin GUO Yianting HU Zhuangqi Institute of Metal Research Academia Sinica Shenyang China professor Institute of Metal Research Academia Sinica Shenyang China 《金属学报(英文版)》1993,6(6):353-357
Proper addition of 0.002 wt-% Mg to cast Fe_3Al alloy may obviously improve the room andhigh temperature tensile properties.Auger spectra show that Mg segregates near grainboundaries as very thin layers.Observation under TEM reveals that a suitable amount of Mgenhances ability of cooperative internal deformation so that the dislocations will ease the con-tinuous slip deformation through grain boundaries.The fracture feature of Fe_3Al alloy is oftransgranular cleavage at room temperature and cracks initiate at grain boundaries. 相似文献
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强化固溶对Al—Zn—Mg—Cu合金力学性能和断裂行为的影响 总被引:25,自引:0,他引:25
研究了强化固溶对提高7075和7055铝合金力学性能的效果,结果表明,逐步升温固溶处理可使最终固溶温度超过多相共晶温度而不产生过烧组织,提高残余可溶结晶相的固溶程度和合金力学性能,强化固溶的7075和7055合金的抗拉强度分别达到660和750MPa,且延伸率保持约10%,一般固溶7055合金的强度仅与强化固溶7075合金的强度相当,断口分析显示,两种合金的断裂属晶内韧窝断民沿晶断裂的混合断裂,强化固溶后,残余结晶相引起的内韧窝断裂减少,沿晶断裂增加。 相似文献
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EFFECTS OF RARE EARTH MIXTURE ON MECHANICAL PROPERTIES OF CuZnAl SHAPE MEMORY ALLOYS 总被引:1,自引:0,他引:1
N.C.Si S.C.Sun Departmentof Materials Engineering Jiangsu University of Science Technology Zhenjiang China 《金属学报(英文版)》1999,12(4):509-514
1.IntroductionWiththedevelopmentofscienceandtechnology,CuZnAlshapememoryalloysarebeingresearcheddeeplyandwidely.Theproblemsinapplicationsofthesealloysarebeingpaidmoreandmoreattention.ThemaindisadvantagesofCuZnAlshapememoryalloysare:largegrainsize(ab… 相似文献
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通过比较不同Al含量的超塑性Zn-Al合金在模拟酸雨溶液中的腐蚀行为,系统研究了超塑性Zn-Al合金在酸雨环境中的腐蚀机理。结果表明,Zn-Al合金在模拟酸雨溶液中发生的腐蚀行为与其显微组织有关。富Al相优先腐蚀,随着合金中Al含量的提高富Al相增多,合金的腐蚀速率反而下降。这是因为ZA4合金与ZA8合金晶界上分布有不连续的富Al相,腐蚀产物不致密,腐蚀坑逐渐向纵深方向发展,腐蚀速率相对较高。而ZA12合金与ZA16合金存在连续分布的富Al相,其表面形成致密的腐蚀产物膜,能有效阻碍反应的进行。 相似文献
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稀土元素Ce和La合金化对AM60镁合金腐蚀行为的影响 总被引:3,自引:0,他引:3
采用电子探针-能谱分析,场发射扫描电镜X射线衍射等方法研究了稀土元素Ce和La合金化对AM60镁合金结构和耐蚀性能的影响.结果表明,Ce和La的加入可在AM60镁合金中形成了富含稀土元素的γ相(MgAlRE);能有效抑制析氢,提高镁合金的耐蚀性能;改善镁合金在含Cl-溶液中的耐蚀性能;腐蚀产物膜的晶态主要成分为铝和锰的氧化物,并含有少量的稀土氧化物和氢氧化物. 相似文献
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The effects of boron addition on defect hardening at room temperature and on high temperatrue creep properties are investigated in the B_2 NiAl intermetallic comopound.It is foundthat boron addition is effective on inereasing the room temperature hardeness on theNi-rich side but it has no effect on the Al rich side of stoichiometry.These obseryationsare attributed to interstitial dissolution of boron in Ni-rich NiAl and to a lack of solubilityand also due to an enrichment at grain boundaries on the Al-rich side.The similar effect is found in high temperature creep resistance of NiAl by bofom addition.The high temperature creep resistance increases on the Ni-rich side but it does not affect the Al-rich side ofoff-stoiciometry. 相似文献
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钯与稀土元素的合金化行为及其尺寸效应 总被引:1,自引:1,他引:0
研究了稀土元素原子尺寸对Pd-RE合金的固溶度、共晶温度和各中间化合物的熔点或分解温度的影响。稀土元素与Pd的合金化行为显示了很强的相似性,借此可以预测某些尚未研究的Pd-RE合金的相稳定性和成分范围。讨论了固溶度及合金化行为与稀土元素电子结构的关系。 相似文献
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微量钪对TiAl基合金高温力学性能的影响 总被引:2,自引:0,他引:2
研究了添加微量钪对具有全层片组织和双态组织的TiAl基合金在900℃的高温力学性能的影响。结果表明,微量Sc可以显著提高TiAl基合金的高温屈服强度及抗压强度。使用金相显微镜和透射电子显微镜详细地分析了试样高温压缩变形前后的显微组织及其变化,在此基础上探讨了合金高温下的塑性变形行为及其微合金化强化机理。 相似文献
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硫含量及显微组织对管线钢力学性能和抗H2S行为的影响 总被引:3,自引:0,他引:3
测试了4种不同硫含量(5×10-6,17×10-6,50×10-6,100×10-6)及不同显微组织管线钢的力学性能和抗H2S开裂性能.结果表明,高硫含量(100×10-6)会导致管线钢中Ⅱ型MnS夹杂物的形成,恶化冲击性能,而对拉伸性能和抗H2S开裂性能不产生明显影响.针状铁素体组织比(多边形铁索体 珠光体)组织具有更好的强韧性,但两种组织的抗H2S开裂性能相反,分析认为这与针状铁素体中大量可动位错对氢的携带和聚集有关. 相似文献
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M.A.Morris M.Leboeuf Institute of Structural Metallurgy University of Neuchtel Neuchtel Switzerland 《中国有色金属学会会刊》1999,(Z1)
1 INTRODUCTIONThecreepresistanceoftwophasetitaniumaluminidealloyshasbeenconfirmedtodependnotonlyonlamellarvolumefractionorgrainsizebutalsoonotherparameterssuchasthemorphologyofeachphase[1-4].Thepresenceoflamellarinterfacesleadstoimprovedcreepresis… 相似文献
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稀土—锆共渗对45钢耐蚀性能的影响 总被引:6,自引:3,他引:3
利用稀土的活化,催渗作用,在气相条件下实现了锆对45钢表面的扩渗,采用SEM-EDS、XPS及XRD对渗层进行了化学成分分析及物相分析,并通过浸泡试验与湿热试验,中性盐雾试验研究了锆的渗入对45钢耐蚀性能的影响,结果表明:锆的渗入明显提高了45钢表面的耐蚀性能。 相似文献
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Compression tests at room and high temperature and creep tests at high temperature have been performed on B2 Nb15Al20V and Nb10Al20V alloys. At room temperature,in the as-cast state, both alloys exhibited significant ductility in compression. The dislocations showed good mobility. Dislocation clusters also triggered the formation of pseudotwins, which resulted in serrated yielding. In steady state creep, deformation occurred by a combination of dislocation glide and climb, giving a homogeneous miphase structure with a few dislocations in the A15 phase but no dislocations in the A2 phase. 相似文献