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用座滴法研究了Ag/W在真空,Ar,H_2及3H_2+N_2气氛下的润湿角及其与温度的关系,并进行了表面及界面分析。结果表明,气氛中的氧分压是影响Ag/W润湿角的主要因素。微量的Ni,Cu,Ce元素可以显著提高Ag/W润湿性,使熔点附近的润湿角从69°降低至10°—20°。 相似文献
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By the sessile drop technique, the wettability of Cu/W systems with the additions of Ni and Cr has been studied under vacuum atmosphere. Effects of Ni and Cr contents and wetting temperatures on the wettability and the wetting mechanisms of copper on W substrate have been investigated in detail. The results show that the wetting angles of Cu on the W substrate are decreased with an increase in the content of Ni or Cr, and also decrease with raising the wetting temperatures. SEM, EPMA, and X-ray diffraction have been used to analyze the interracial characteristics of the CuNi/W and CuCr/W systems. The results reveal that there is a transition layer about 2- 3μm in the interface of Cu-4.0 wt pct Ni/W, in which the interrnetallic phase Ni4W is precipitated. As to CuCr/W system, no reaction occurs at the interface. The two factors are that the contents of Cr and Ni and the infiltration temperature must be chosen appropriately in order to control the interfacial dissolution and reaction when the Cu- W alloys are prepared by the infiltration method. 相似文献
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H.Z. Huang X.Q. Wei L. Zhou X.D. Liu G.L. Guo 《金属学报(英文版)》2006,19(4):251-257
The potential of using a hypoeutectic, instead of eutectic, Sn-Zn alloy as a lead-free solder has been discussed. The nonequilibrium melting behaviors of a series of Sn-Zn alloys were examined by differential thermal analysis. It was found that at a heating rate of 5℃/min, Sn-6.SZn exhibited no melting range. Dipping and spreading tests were carried out to characterize the wettability of Sn-Zn alloys on Cu. Both tests exhibited that Sn-6.5Zn has significantly better wettability on Cu than Sn-9Zn. The reaction layers formed during the spreading tests were examined. When the Zn concentration fell between 2.5wt%-9wt%, two reaction layers were formed at the interface, a thick and flat Cu5Zn8 adjacent to Cu and a thin and irregular Cu-Zn-Sn layer adjacent to the alloy. Only a Cu0Sn5 layer was formed when the Zn concentration decreased to 0.5wt%. The total thickness of the reaction layer(s) between the alloy and Cu was found to increase linearly with the Zn concentration. 相似文献
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J.B. Li) J.P. Niu) X. Wang) ) College of Machinery Shenyang University Shenyang China) BenxiIron Steel Company Benxi China 《金属学报(英文版)》1999,12(4):705-707
1.IntroductionNiCrMoalloycastironisoftenusedtomakerollers.AddingSiCparticlesinittoformcompositecanimproveitswearresistanceandimpactstrengthproperties.ThismainlydependsonthestateofdistributionofSiC,SiCfactorandthecombinationstrengthbetweenthetwos.Toi… 相似文献
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EFFECTSOFSMALLAgADDITIONSONMECHANICALPROPERTIESANDMICROSTRUCTUREOFALLOY2195¥HuangBiping;ZhengZiqiao;YinDenfeng;MoZhiming(Depa... 相似文献
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20CrMo钢淬火后,在600,450和200℃回火,可以得到有上、下屈服点、没有上屈服点只有屈服平台没有物理屈服现象等3种屈服曲线。本文通过对此3种材料施以不同预变形,研究了Cottrell气团对初始屈服抗力σ0和疲劳门槛值ΔKth的影响。 相似文献
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接地电阻对地电场观测的影响及克服方法 总被引:1,自引:0,他引:1
论述了测量电极的接地电阻对振幅和相位测量精度的影响规律,提出了克服接地电阻影响,提高野外观测精度的切实可行的方法和技术。 相似文献
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利用金相法和电子探针研究了微量元素P,C,Si和Nb对采用低偏析均质化技术炼制的Cr-Ni-Mn-N奥氏体抗氢钢凝固组织和微观偏析的影响。结果表明,降低P,C及Si的含量有利于Cr-Ni-Mn-N奥氏体凝固组织枝晶细化,Nb保持适当含量对枝细化有利,分别减少,P,C,Si和Nb的实验钢中的含量不仅能大幅降低元素自身的偏析,而且不同程度地影响到其它元素偏析。 相似文献
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Ag含量对纤维相强化Cu-Ag合金组织及性能的影响 总被引:1,自引:0,他引:1
通过冷拉拔结合中间热处理制备了不同Ag含量的纤维相强化Cu—Ag合金,研究了Ag含量对合金组织形态、强度和电导率的影响.Ag含量在6%-24%范围内的合金铸态组织包含初生α枝晶、共晶体和次生相.在拉拔过程中,共晶体及次生相均演变成细密的纤维形态.随Ag含量的升高,共晶体及次生相数量增多,合金强度及应变硬化速率升高,电导率下降,尤其当Ag含量增加使合金组织中的共晶纤维束增多并呈连续网状分布时,电导率下降更为明显.高Ag含量合金中共晶体纤维束的强化效应明显高于低Ag含量合金中次生相纤维的强化效应,但其对合金导电性能的损害程度也高于后者. 相似文献
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The Bi-2223/Ag tapes were prepared with spray-died powders, which are of different particle sizes and phase assemblages by varying the annealing time in pure oxygen. Longer time annealing degraded the reactivity of precursor powder, which in turn resulted in an incomplete conversion from precursors to Bi-2223, porosity core and misaligned grains in fully processed tapes. The best Jc in short pressed samples varied from 29.7 to 47kA/cm2 for the tapes made from different powders. 相似文献
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提高W—Ni—Cu合金膨胀系数等性能的实例分析 总被引:5,自引:0,他引:5
为提高WNiCu合金的膨胀系数等性能,提出了选择添加元素的原则,进行了金属Mn、Ag粉末对WNiCu合金性能影响的研究;并分析、讨论了影响WNiCu合金性能的因素及研制具有良好综合性能的钨合金的可能途径 相似文献
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微晶化对高温合金K38G在CO气氛中腐蚀的影响 总被引:1,自引:0,他引:1
研究了高温合金K38G在850-1000℃下CO气氛中的腐蚀以及微晶化对高温合金K38G在CO气氛中腐蚀的影响。结果表明:铸态K38G合金在CO气氛中表面形成Cr2O3,TiO2和Cr7C3,合金发生严重的内腐蚀,腐蚀动力不基本符合抛物线规律; 相似文献
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