稀土Ce对锌电积用Pb-Ag-Ca-Sr四元合金阳极板性能的改进

Pb-Ag-Ca-Sr四元合金具有较好的力学性能、导电性能和耐腐蚀性能,但合金元素分布不均、性能不稳定、稀贵金属损耗大、制作成本高,制约其在湿法炼锌电积阳极的广泛应用。通过熔炼工艺向Pb-Ag-Ca-Sr四元合金中添加稀土Ce,然后进行轧制,分别考察稀土Ce对Pb-Ag-Ca-Sr四元合金显微组织、力学性能、导电性和耐腐蚀性能的影响。结果表明,添加质量分数为0.04%的稀土Ce后,Pb-Ag-Ca-Sr四元合金的晶粒明显得到细化,抗拉强度、屈服强度和电导率分别提高9%、23%和1.75%,耐腐蚀性能也得到明显提高,稀土Ce对Pb-Ag-Ca-Sr四元合金阳极材料综合性能提升作用强于轧制工艺。     

Zn及热处理制度对2056铝合金力学性能及局部腐蚀行为的影响

通过拉伸性能测试、晶间腐蚀(IGC)、剥落腐蚀(EXCO)实验、极化曲线测试及透射电镜(TEM)分析,研究Zn元素和不同热处理制度对2056铝合金室温常规力学性能、抗晶间腐蚀性能、抗剥落腐蚀性能及微观组织的影响。结果表明,微量Zn均匀存在于合金的各个位置,可促进S′相的析出和提高合金强度;减小晶内与晶界的电化学腐蚀动力,使晶界析出的S相数量减少并不连续分布,无沉淀析出带(PFZ)变窄,提高合金的抗晶间腐蚀性能和抗剥蚀性能。与T6处理态相比,经T8处理后,晶内析出的S′相数量增加、尺寸减小、分布均匀,合金的强度显著提高,塑性降低;同时,沿晶界析出的S相数量减少,PFZ变窄,合金的抗晶间腐蚀和抗剥落腐蚀能力提高。在3.5%的NaCl溶液中进行的极化曲线测试也表现出相同的结果。     

7075铝合金化学镀对镍磷合金镀膜组织和性能的影响

金属表面处理直接影响7075铝合金的力学性能及耐腐蚀性能.以7075-T6铝合金为基体,采用化学镀(EN)技术在光滑基体表面均匀镀覆一定厚度的镍磷(Ni-P)镀膜,镀膜厚度分别为3.64、5.87和7.33 μm,并通过扫描电子显微镜(SEM)、X射线衍射(XRD)、硬度测试及电化学工作站等手段分析膜层特性及膜厚对70...     

Nd对Mg-11Li-3Al-2Zn-0.2Zr合金组织、力学性能及腐蚀行为的影响

研究稀土Nd对均匀化态Mg-11Li-3Al-2Zn-0.2Zr合金组织、力学性能及腐蚀行为的影响.通过真空感应熔炼制备镁锂合金铸锭, 经均匀化处理(280 ℃, 24 h)得到均匀化态Mg-11Li-3Al-2Zn-xNd-0.2Zr(x=0, 0.5, 1.0, 1.5)合金.采用XRD和SEM分析合金的显微组织, 并对合金进行拉伸试验和断口分析.采用电化学法和析氢失重法研究合金在3.5 %NaCl溶液中的腐蚀行为.结果表明:Mg-11Li-3Al-2Zn-0.2Zr合金主要含有β-Li、AlLi、MgLi₂Al相, Nd的加入使合金中形成NdAl3相.随着Nd含量的增加, 合金的强度和塑性呈先增大后降低的趋势. Mg-11Li-3Al-2Zn-1Nd-0.2Zr合金表现出较优的力学性能, 其抗拉强度和延伸率相对于Mg-11Li-3Al-2Zn-0.2Zr合金分别提高了28.8 %和51.3 %.稀土Nd的添加使合金的耐蚀性能提高.      

Corrosion and mechanical properties of AM50 magnesium alloy after being modified by 1 wt.% rare earth element gadolinium

In order to improve the corrosion and mechanical properties of AM50 magnesium alloy, 1 wt.% Gd was used to modify the AM50 magnesium alloy. The microstructure, corrosion and mechanical properties were evaluated by X-ray diffraction(XRD), scanning electron microscopy(SEM), energy dispersive spectroscopy(EDS), electrochemical and mechanical stretch methods. The results indicated that β-Mg17Al12 phase decreased and Al2Gd3 and Al0.4GdMn1.6 phase existed after Gd addition. Because of the Gd addition, the grain of AM50 magnesium alloy was refined significantly, which improved the tensile strength of AM50 magnesium alloy. The decreasing of β phase improved the corrosion resistance of the magnesium alloy. The fracture mechanism of the Gd modified AM50 magnesium alloy was quasi-cleavage fracture. The corrosion residual strength(CRS) of AM50 magnesium alloy was improved after 1 wt.% Gd addition.     

氮元素对Cr13超级马氏体不锈钢组织及性能的影响

摘要：为了提高超级马氏体不锈钢的性能以满足油气开采的使用要求,在Cr13超级马氏体不锈钢中添加质量分数为0.065%的N元素,并采用金相观察、SEM、拉伸试验、电化学测试等方法,研究N元素对Cr13超级马氏体不锈钢组织、力学性能及耐蚀性能的影响。研究发现,N元素能细化原奥氏体晶粒、对组织中的回火马氏体有一定的“短化”作用,并且能有效减少组织中的δ铁素体、增加奥氏体的含量。在力学性能方面,适量的N元素因可以细化奥氏体晶粒和短化马氏体从而增加晶界和亚晶界,所以能有效提高试验钢的屈服强度和抗拉强度。耐蚀性能方面,电化学实验表明,适量的N元素能提高钝化膜的保护能力和再钝化能力,所以在一定程度上能有效提高试验钢的耐蚀性能。     

双级时效对含钪Al-Cu-Li-Zr合金力学性能与抗腐蚀性的影响

采用室温力学性能测试、透射电镜分析和腐蚀实验等方法,研究了双级时效对含钪Al-Cu-Li-Zr合金的力学性能与抗腐蚀性的影响.结果表明,经双级时效处理的合金可获得较佳的强塑性组合,与T8峰时效态合金相比,双级时效态合金可在不降低强度的情况下提高延伸率;T1相是合金的主要沉淀强化相,合金经双级时效处理后,晶内析出的T1相细小弥散且分布均匀,从而改善合金的抗腐蚀性.     

时效制度对Al–Zn?Mg合金组织和抗应力腐蚀性能的影响

采用慢应变速率拉伸应力腐蚀、室温拉伸、透射电镜等检测方法，研究传统T5、T73时效处理，以及新型T5I4、T5I6断续时效处理对Al–Zn?Mg合金微观组织、室温拉伸性能及抗应力腐蚀性能的影响。结果表明:断续时效T5I4处理后材料抗拉强度为400.0 MPa，明显高于传统T5及T73态样品，但材料抗应力腐蚀性能变差，应力腐蚀敏感系数为5.7%；而经断续时效T5I6处理后，材料的抗拉强度为408.5 MPa，较T5I4态相比有所提升，与此同时抗应力腐蚀性能也得到明显改善，应力腐蚀敏感系数为3.2%，该值明显小于T5I4及T5态；T5I4态晶内析出相平均粒径为2.0 nm，体积分数为8.8%，均明显小于其他3种时效制度，其晶界析出相为细小且连续分布的点状析出相；而经T5I6时效处理后晶内析出相体积分数为24.6%，明显大于其他3种时效制度，晶内析出相平均粒径（4.1 nm）较T5I4态有所增大，但依然小于T5、T73态，其晶界处析出相与T5I4态相比更加粗大，呈断续分布形貌。      

Phenomenological observations on mechanical and corrosion properties of thixoformed 357 alloys: A comparison with permanent mold cast 357 alloys

In the present study, the mechanical and corrosion properties of thixoformed 357 alloys were examined with different reheating temperatures, and the results were compared with those of permanent mold cast (PMC) 357 alloys. It was found that the thixoforming process significantly improved the mechanical properties (i.e., tensile elongation, impact energy, and resistance to fatigue crack propagation) and the corrosion resistance of 357 alloys. A 380 pct increase in tensile elongation and a 120 pct increase in impact energy were, for example, observed with the thixoforming process of 357 alloy in the T1-tempered condition, as compared to the PMC counterparts. The impact energy was extremely sensitive to reheating temperature due to the coarsening of eutectic Si particles. The resistance to fatigue crack propagation was also much higher for the thixoforming process than the PMC process in the T1-tempered condition. The resistance to both general corrosion and stress corrosion cracking was also greatly improved with thixoforming process. The present observations strongly suggest that the enhancement with thixoforming 357 alloy is largely associated with the size and shape of eutectic Si particles.     

稀土元素对低温铝基钎料性能影响的研究

本文研究了稀土元素Ｙ、Ｃｅ对Ａｌ－Ｚｎ－Ｃｕ－Ｓｉ系列低温铝基钎料的熔化温度、钎焊工艺性、电极电位及其接头的机械性能及抗腐蚀性能的影响。结果表明：少量Ｙ、Ｃｅ的加入，对钎料的熔化温度影响不大，能提高钎料的钎焊工艺性；稀土Ｙ、Ｃｅ能细化晶粒，改变组织的分布状态，不改变钎料的电极电位，但却提高了钎焊接头的机械性能和抗腐蚀性。     

Microalloying of Sc, Ni, and Ce in an advanced Al-Zn-Mg-Cu alloy

Using transmission electron microscopy (TEM), scanning electron microscopy, X-ray diffraction (XRD), and optical microscopy, the effects of microalloying elements of Sc, Ni, and Ce on the microstructure of a new super-high-strength ingot metallurgy (IM)/Al-Zn-Mg-Cu alloy (C912) have been correlated with mechanical properties and stress corrosion cracking (SCC) behavior. Using microalloying with Sc, Ni, and Ce, the C912 alloy can exhibit very high strength and good SCC resistance. Compared to the baseline C912 alloy, Sc refines the microstructure and retards recrystallization, Ni promotes the development of matrix precipitates, which enhance the strength and SCC resistance, and Ce has little effect on alloy strengthening in the three microalloying additions studied. The Sc-containing alloy (C912S) is the most attractive and even exhibits higher strength (ultimate tensile strength (UTS) greather than 660MPa) than the new Alcoa aluminum alloy 7055 and the Russian alloy B96, which have the highest strengths of the commercial IM/Al-Zn-Mg-Cu alloys.     

Microstructure, tensile and creep properties of as-cast Mg-3.8Zn-2.2Ca-xCe（x=0, 0.5,1 and 2 wt.%） magnesium alloys

The microstructure and mechanical properties of as-cast Mg-3.8Zn-2.2Ca alloy with different Ce contents were investigated by both optical and electron microscopy, X-ray diffraction, differential scanning calorimetry analysis, tensile and creep tests. The results indi-cated that adding 0.41 wt.%-1.83 wt.% Ce could refine the grains of the alloy, and the grain size gradually decreased as the Ce content in-creased. Furthermore, addition of either 0.41 wt.% or 0.89 wt.% Ce caused the morphology of the Ca2Mg6Zn3 phase to change partially from semi-continuous block to discrete fine particles. However, after adding 1.83 wt.% Ce, portions of the Ca2Mg6Zn3 and Mg12Ce phases were mixed and this Ca2Mg6Zn3+Mg12Ce eutectic changed to a different coarse semi-continuous morphology. In addition, addition of 0.41 wt.%-1.83 wt.% Ce improved the tensile and creep properties of the alloy. Amongst these Ce-containing alloys, the alloy with 0.89 wt.% Ce exhibited the best ultimate tensile strength and elongation while the alloy with 1.83 wt.% Ce had the best yield strength and creep properties.     

Mechanical properties of the A356 aluminum alloy modified with La/Ce

The research of rare earths for the synthesis of materials with improved mechanical performance is of great interest when they are considered for potential applications in the automotive industry. In this regard, the effect on the mechanical properties and microstructure of the automotive A356 aluminum alloy reinforced with 0.2 (wt.%) Al-6Ce-3La (ACL) was investigated. The ACL was added to the melted A356 alloy in the as-received condition and processed by mechanical milling. In the second route, the effect of the ACL processed by mechanical milling and powder metallurgy techniques was investigated, and compared with the results obtained from the A356 alloy strengthened with ACL in the as-received condition. Microstructural properties were evaluated by means of X-ray diffraction in order to observe the solubility of Ce/La in the Al matrix. In addition, electron microscopy was employed in order to investigate the effect of milling time on the size and morphology of La/Ce phase under milling process. Mechanical properties of the A356 alloy modified with ACL were measured by hardness and tensile test. For comparison unmodified specimens of the A356 were characterized according to the previous procedure. The microstructural and mechanical characterization was carried out in specimens after solution and artificial aging. Observations in scanning electron microscopy indicated a homogeneous dispersion of La/Ce phases by using both routes; however, mechanical results, in the modified A356 alloy with the ACL in the as-received condition, showed an improvement in the mechanical performance of the A356 alloy over that reinforced with the ACL mechanically milled.     

Corrosion Behavior of Welded Joints of Al-6Mg Alloy with Trace Scandium Addition

Al-6Mg alloy with trace Sc addition was prepared by means of melting-casting.The samples of the welded joints of Al-6Mg alloy with trace Sc addition were made by method of manual argon-arc welding.Neutral salt spray test was carried out by referring to GB/T10125-1997 and GB6384-1986 practice.Exfoliation testing was carried out in accordance with the method of Al-Mg alloy exfoliation corrosion test.The corrosion behaviors of the welded joints of AlMg alloy with high level of Mg and trace Sc addition were studied.The microstructures of the welded joints were observed by using optical microscope and transmission electron microscope.The corrosion resistance mechanism of the alloy was also involved.This work intended to determine if the welded joints of Al-6Mgalloy with trace Sc addition can have excellent corrosion resistance, when their strength are clearly improved.The results show that trace content of Sc refines the grains of alloys effectively, raises remarkably the corrosion resistance of the welded joints of Al-6Mg alloy with trace Sc addition.The corrosion resistance mechanisms are that there is free of continuous grain boundary precipitation or network which could be susceptible to corrosion in the microstructure of welded joints.     

稀土元素Ce对HSn62-1黄铜组织和脱锌腐蚀性能的影响

研究了加入稀土元素Ce对Hsn62-1黄铜组织的影响,利用腐蚀试验和电化学试验研究了稀土元素Ce的加入对合金耐脱锌腐蚀性能的影响。研究表明,加入稀土元素Ce明显地细化了合金的组织,使粗大的α、β板条状组织变成短小的细板条状组织。加入稀土元素Ce可以明显改善黄铜耐脱锌腐蚀性能。     

稀土铈对22MnCrNiMo钢耐腐蚀性能的影响

为了研究稀土对系泊链钢耐蚀性能的影响，冶炼铈含量不同的稀土系泊链钢，利用稀土在钢中的有利作用,力求进一步提高系泊链钢的耐蚀性能。试验用22MnCrNiMo稀土钢由10 kg真空感应炉冶炼，热轧成17 mm板坯，经930 °C二次淬火加620 °C回火处理，通过质量法、极化曲线法和交流阻抗法研究铈对22MnCrNiMo钢耐腐蚀性能的影响。结果表明，添加稀土铈后，不同铈含量试验钢的抗腐蚀性能均有所提高，钢中铈的最佳质量分数为0.143%。此含量下，试验钢组织的均一性最佳，钢中夹杂转变为稳定性高的稀土类球状夹杂，使得试验钢在任一浸泡周期内的腐蚀速率均为最小，除锈后的腐蚀痕迹最轻；容抗弧半径达到最大，即反应电阻到达最大；阳极极化曲线位于其他试验钢阳极极化曲线的左边，即阳极电流密度变小，反应阻力增大。所以铈可以提高22MnCrNiMo钢耐腐蚀性能，当钢中铈的质量分数为0.143%时，试验钢的抗腐蚀性能表现最佳。     

微量钪(Sc)对5A01合金性能与显微组织的影响

研究了在5A01合金基础上添加0．2％Sc和0．3％Sc后合金的显微组织、力学性能、腐蚀性能及焊接性能。结果表明，微量Sc的加入，初生Al3Sc或Al3（Sc，Zr）粒子可成为有效的非均质晶核，大大地细化合金的铸态晶粒，次生Al3Sc或Al3（Sc，Zr）粒子，能有效地钉轧位错和亚晶界，稳定亚结构并强烈抑制合金的再结晶。因此，加入Sc后的试验合金基体及焊接强度提高，腐蚀性能和焊接性能与5A01合金相当甚至更好。     

Effect of cerium addition on microstructure and mechanical properties of Al-Zn-Mg-Cu alloy

Effect of cerium addition on the microstructure and mechanical properties of an Al-Zn-Mg-Cu alloy have been investigated. In this study, aluminum alloys with up to 0.4% cerium content have been prepared by melting, metal mould casting followed by thermo-mechanical processing. The alloys were extensively characterized by optical and transmission electron microscopy, followed by mechanical property examination by tensile tests as well as nanoindentation tests. It was observed that cerium addition results in up to 5% grain refinement of the cast dendritic structure as well as up to 38% refinement of the heat treated microstructure. Transmission electron microscopy (TEM) has revealed the uniform distribution of fine GP zones and some semi coherent β(MgZn₂) precipitates in the Al rich matrix. Further TEM results show that when the Ce content was changed from 0.1% to 0.4%, precipitate size increased from 5 to 50nm and the precipitate morphology changed from spherical to needle shape. Evaluation of mechanical properties through tensile and nano-indentation tests have exhibited that both Young’s modulus and tensile strength increases with Ce addition up to 0.3% and subsequently decrease.     

微量稀土对铸态Cu-3.0Si-2.0Ni合金组织及性能的影响

加入适量的稀土元素能有效改善铜合金的组织和性能.铸态Cu-3.0Si-2.0Ni合金中添加稀土Ce后,进行熔炼及热处理试验,再通过室温拉伸、导电率试验和金相观察,研究了微量Ce对铸态Cu-3.0Si-2.0Ni合金组织与性能的影响.结果表明:铸态合金晶粒随着Ce含量的升高呈现先减小后递增的趋势;铸态合金的抗拉强度和导电性随着Ce的增加分别先升高后减低;当Ce的质量分数为0.06%时,铸态合金的抗拉强度最高、导电性最强.     

钼对S30432耐热钢组织和性能的影响

 为了明确是否应在国产S30432钢中加入钼,研究了0.32%Mo对S30432耐热钢组织和性能的影响及机理。利用SEM、TEM和Thermo-Calc软件研究了钼对S30432钢析出相和基体的影响;通过650 ℃高温瞬时拉伸试验和高温蠕变断裂试验研究钼对S30432钢高温力学性能的影响;采用电化学试验评价了钼的添加对S30432钢耐腐蚀性能的影响。结果表明,添加钼对S30432钢的高温力学性能和耐腐蚀性能有益。在S30432钢中添加0.32%Mo,提高了其650 ℃时的屈服强度和抗拉强度,延长了短时蠕变断裂时间并提高了断裂后的硬度。但长时蠕变后钼对S30432钢强度提高的作用不明显。含钼的S30432钢具有更高的自腐蚀电位、点蚀破裂电位和更低的晶间腐蚀敏感性。腐蚀形貌观察发现含钼钢中点蚀坑的数量较少、尺寸较小,晶间腐蚀程度较轻。