新型团球硅相增强锌铝合金的研究

选择多种成分的锌铝合金,以硅为增强相,扩大硅的成分范围,采用复合钠盐和稀土混合物对合金中的硅进行变质处理,测定试验合金的力学性能和常温、高温耐磨性,优选综合力学性能较好的试样,进行离心铸造、轴瓦抱轴和高温磨损测试,观察其显微组织。结果表明,锌铝合金中加入硅相后,其综合力学性能进一步提高,采用钠盐和稀土混合变质,两者的变质作用互相促进。根据离心铸造测试结果,建议转速在500~600 r/min之间为好,硅相的浓度分布是从铸件外层到内壁逐渐增大,优选合金的使用温度比ZA27合金明显提高,这归功于硅相的骨架作用。     

球团硅相增强ZA35合金基复合材料及其耐磨性

为了提高锌铝合金在干摩擦条件下的耐磨性以进一步拓宽其应用范围,在ＺＡ３５合金中加入２．５％－５．５％Ｓｉ,并用自制钠盐变质剂对含硅合金进行处理,制得变质硅相增强ＺＡ３５合金基复合材料。     

耐热低膨胀高硅铝合金的成形与性能

利用超声振动半固态流变压铸成形的方法制备出含20%Si的AlSiCuMgNiRE合金,研究了这种合金的组织、高温性能及热膨胀性能。结果表明,P与稀土复合变质的高硅铝合金,300℃的高温抗拉强度达到167 MPa,室温强度达到310 MPa;25~300℃内的热膨胀系数为17.4×10-6(1/℃)。添加2%Fe的高硅铝合金,由于针状富Fe相割裂基体,力学性能大幅度降低。而通过超声处理可改变富Fe相的形态,其室温及高温力学性能提高。     

稀土Nd对Zn-25Al-2.5Si铸态组织及力学性能的影响

以Zn-25Al-2.5Si合金为基体材料,通过常规铸造方法制备了不同稀土含量的锌铝合金.分析了稀土Nd对实验合金组织和力学性能的影响.结果表明,添加稀土后,在锌铝合金中,Nd与Al、Zn等形成复杂成分化合物,其硬度高,热硬性好,分散于晶界和枝晶中,细化了组织,且有效地阻碍了高温时基体的变形和晶界移动.Nd使合金力学性能得到提高,尤其高温强度和硬度提高显著.其中添加0.8 wt%Nd的合金综合性能最好,180 ℃时的抗拉强度提高48.8%,硬度提高67.4%.     

稀土复合变质处理对Al-Si合金性能的影响

采用Ce-La复合稀土对Al-20%Si合金进行变质处理,考察了稀土复合变质对Al-Si合金力学性能、耐磨性能的影响,研究了冷却速度对合金力学性能的影响。结果表明:Ce-La复合变质剂对Al-20%Si合金具有双变质作用,当稀土Ce的添加量为0.5%,La的添加量为0.6%时,Al-Si合金的力学性能最好,抗拉强度和伸长率分别为268.5 MPa、0.52%;Ce-La复合变质剂能细化合金,提高合金耐磨性;稀土共晶硅对冷却速度一定程度上较为敏感,冷却速度的提高可以有效细化合金。     

稀土变质消除铝合金压铸件中硬质点

初生硅和AlSiMnFe金属间化合物是造成铝合金压铸件中硬质点区域的主要因素 ,常规钠盐变质不能细化初生硅和Fe相 ,含有一定比例La ,Ce ,Pr ,Nd和Yb的特殊配制的稀土合金不仅能细化共晶硅 ,而且能细化初生硅并改善Fe相形貌。其中初生硅可细化到小于 10 μm ,因此能有效消除铝合金压铸件中的硬质点区域     

稀土变质消除铝合金压铸件中硬质点

初生硅和AlSiMnFe金属间化合物是造成铝合金压铸件中硬质点区域的主要因素,常规钠盐变质不能细化初生硅和Fe相,含有一定比例La,Ce,Pr,Nd和Yb的特殊配制的稀土合金不仅能细化共晶硅,而且细化初生硅并改善Fe相形貌,其中初生硅可细化到小于10μm,因此能有效消除铝合金压铸件中的硬质点区域。     

Al-RE-Cu-Mn-Si铸造铝合金高温性能研究

采用SEM、EDX对Al-RE-Cu-Mn-Si铸造铝合金的高温性能进行了研究,分析了合金微观组织形貌特征和相的成分特点.结果表明,该合金在350～400℃高温下力学性能未有明显下降,比一般耐热铝合金的承温能力明显偏高,这与合金中含有高温稳定的稀土化合物相直接相关,该化合物在晶界和枝晶间分布对高温塑性滑移有明显的阻碍作用.     

稀土对泡沫锌铝合金组织和阻尼性能的影响

利用负压渗流法制备出稀土泡沫锌铝合金,研究稀土La和Ce的添加量对泡沫锌铝合金组织和阻尼性能的影响。结果表明：在泡沫锌铝合金中加入Al-10?或Al-10%La中间合金细化了组织,同时提高了泡沫锌铝合金的阻尼能力;稀土元素的添加量为0.3%时（质量分数）可获得最佳的变质效果和最高的阻尼能力;相对于未变质而言,阻尼能力提高了近3倍;稀土泡沫锌铝合金的阻尼机制与相界面的非弹性粘滞性流动有关,合金的相界面越多,阻尼性能就越好。     

不同变质剂对铝合金组织及性能的影响

在合金熔炼的过程中分别加入RE(镧铈混合稀土)、Al-Ti-B和铝钪合金对合金进行变质处理,研究不同变质剂对合金组织及力学性能的影响。结果表明,RE、Al-Ti-B和铝钪都是通过改变合金中硅相的颗粒大小来改变合金的铸态组织,从而提高合金的综合力学性能。     

Improvement in mechanical properties of hypereutectic Al-Si-Cu alloys through sonosolidified slurry

For the wider applications,it is necessary to improve the ductility as well as the strength and wear-resistance of hypereutectic AlSi-Cu alloys,which are typical light-weight wear-resistant materials.An increase in the amounts of primary silicon particles causes the modified wear-resistance of hypereutectic Al-Si-Cu alloys,but leads to the poor strength and ductility.It is known that dual phase steels composed of hetero-structure have succeeded in bringing contradictory mechanical properties of high strength and ductility concurrently.In order to apply the idea of hetero-structure to hypereutectic Al-Si-Cu alloys for the achievement of high strength and ductility along with wear resistance,ultrasonic irradiation of the molten metal during the solidification,which is called sono-solidification,was carried out from its molten state to just above the eutectic temperature.The sono-solidified Al-17Si-4Cu alloy is composed of hetero-structure,which are,hard primary silicon particles,soft non-equilibrium a-Al phase and the eutectic region.Rheo-casting was performed at just above the eutectic temperature with sono-solidified slurry to shape a disk specimen.After the rheo-casting with modified sonosolidified slurry held for 45 s at 570 oC,the quantitative optical microscope observation exhibits that the microstructure is composed of 18area%of hard primary silicon particles and 57area%of soft a-Al phase.In contrast,there exist only 5 area%of primary silicon particles and no a-Al phase in rheo-cast specimen with normally solidified slurry.Hence the tensile tests of T6 treated rheo-cast specimens with modified sono-solidified slurry exhibit improved strength and 5%of elongation,regardless of having more than 3 times higher amounts of primary silicon particles compared to that of rheo-cast specimen with normally solidified slurry.     

Refinement of the primary Si particles in hypereutectic aluminum alloy

Al-Si alloys, with such excellent properties as low weight, low thermal expansion coefficient, and high wear-resistance, are ideal materials for the automobile and aerospace industries. However, their applications have been hampered by the coarsening of the primary-Si particles in Al-Si alloys. In this study, simple plastic deformation was used to reduce primary-Si particles and to improve the wear-resistance and mechanical strength of Al-Si alloys. Experimental results showed that mechanical rolling decreased the grain size of primary-Si particles in Al-Si alloys and reduced the variation in silicon particle size. After 60%-roll-reduction, the alloy showed an improved tensile strength of 340 MPa, which is attributed to the work hardening of the aluminum matrix and the dispersion strengthening of the primary-Si particles. Data from wear-resistance testing showed that rolling led to a reduction in wear loss. This improvement in wear resistance is due to the particle size refinement of silicon at a high percentage-roll-reduction.     

Zn-Al钎料钎焊Cu/Al接头组织和性能(英文)

使用不同成分的Zn-Al钎料对铜铝异种金属进行火焰钎焊,研究其力学性能。利用光学显微镜、扫描电镜和能谱研究不同Zn-Al钎料对Cu/Al钎焊接头钎焊性、力学性能及显微组织的影响。结果表明:随着Al含量的增加,Zn-Al钎料在Cu和Al上的铺展面积逐渐增大。当钎料中Al含量为15%时,Cu/Al接头的抗剪强度达到最大值88MPa;随着组织的变化,钎缝硬度值呈现HV122到HV515不等的分布。另外,钎缝组织的成分主要为富Zn相和富Al相,但是当钎料中Al含量为2%和15%以上时,靠近Cu侧的界面处会分别形成CuZn3和Al2Cu两种完全不同的金属间化合物。研究Zn-Al钎料中铝含量对Cu/Al接头界面化合物类型的影响。     

A Study of Factors Influencing Spectrochemical Analysis of Al-Si Alloys

A series of samples of Al-Si alloys, up to the eutectic composition, was prepared from metal which was intentionally modified by addition of sodium salt flux and also from metal receiving no intentional modification. The samples were examined with an electron microprobe to compare the silicon particle distributions in the modified and unmodified samples. X-ray analysis was conducted using primary and secondary excitation. The effect of surface preparation upon X-ray analysis was also studied. Results obtained by optical emission analysis on this alloy system are discussed.     

渗硼对45钢耐液态金属腐蚀性能影响的研究

对经过渗硼处理的45钢在液态Zn、Al和Zn-Al合金中的耐蚀性进行研究。结果表明：渗硼处理后45钢在液态Zn、Al和Zn—Al中的耐蚀性大为提高；硼化物层对Zn、Zn—Al合金具有良好的耐蚀性，在Al液中的耐蚀性略低。表明钢的渗硼处理在耐液态金属腐蚀上有较好的应用前景。硼化物在液态Zn、Al和Zn—Al液中的腐蚀是硼化物的均匀溶解过程，没有出现择优腐蚀。     

稀土氧化物强化高铝锌基合金的研究

研究了稀土氧化物对高铝锌基合金的力学性能和高温强度的影响，并利用扫描电镜观察了辞铝合金的显微组织及断口形貌。结果表明，稀土氧化物弥散分布于合金基体中，使晶粒细化，有效地阻碍了基体变形，强度、硬度分别提高33％和45％，高温强度也有所改善。     

复合变质对Al-20%Si合金耐磨性能的影响

在不同P、RE添加量下对P-RE复合变质和未变质的过共晶铝硅合金的耐磨性进行了研究。结果表明:P-RE复合变质明显提高了合金的耐磨性,当加入0.08%P和0.6%RE时,合金的耐磨性达到最佳,磨损失重量从未变质的5.2mg降低到4.225mg,减少了19%。磨损主要为磨粒磨损,磨粒来源是硅相的破碎剥落。合金耐磨性能的改善与复合变质引起的共晶硅和初晶硅颗粒的细化和合金强度、塑性的提高有关。     

1060铝钎缝耐腐蚀性分析

以1060纯铝作为母材,选取Zn-Al-Ag,Zn-Al,Sn-Zn,Zn-Cd-Ag等4种钎料,采用氧乙炔火焰钎焊工艺制备钎焊接头,采用盐浴浸泡方法加速腐蚀,分析了4种钎缝的耐腐蚀性. 通过宏观形貌观察、极化曲线测试、失重分析和显微组织观测,综合评价了钎缝的耐腐蚀性. 结果表明,在所分析的3个合金系中,Zn-Al系钎料钎缝耐腐蚀性能较好,Zn-Cd-Ag钎缝耐腐蚀性次之,Sn-Zn钎缝的耐腐蚀性最差. 对盐浴腐蚀而言,Zn82Al13Ag5比Zn98Al更耐腐蚀. 而对于电化学腐蚀而言,银的加入能够进一步提高Zn-Al系钎料钎缝的耐腐蚀性能.     

Corrosion behavior of Fe-Cr and Fe-Ni-base commercial alloys in flowing Ar-42.6%O2-14.7%Br2 gas mixture at 700 °C

The corrosion behavior of Fe-Cr and Fe-Ni-Base commercial alloys has been investigated in an argon-42.6% oxygen-14.7% bromine gas mixture at 700 °C which was one of the environments encountered in the UT-3 thermochemical water decomposition reaction process to produce hydrogen. The test alloys were type 304 and 310 stainless steels, Incoloy 800, and Incoloy 825. Two-dimensional thermodynamic phase stability diagrams were constructed for iron, chromium, nickel, and titanium to predict the condensed corrosion products that are stable with respect to the representative alloying elements when the alloy is exposed to the argon-42.6% oxygen-14.7% bromine gas mixture at 700 °C. The oxides were thermodynamically stable phases with respect to the corresponding metals. Post-reaction treatment of test alloys included discontinuous mass-change measurements, scanning electron microscopy (SEM), electron probe micro-analysis (EPMA) for morphological and compositional investigation of the corrosion products, and the X-ray diffraction (XRD) for phase identification. XRD identified oxides and spinels as corrosion products but low-melting metal bromides were detected for all alloys with deleterious effects on high-temperature properties of these alloys during exposure to the environment. The poor corrosion resistance of the test alloys was mainly caused by the cracking and spalling of iron and chromium-rich oxides and further growth of various metal bromides beneath the oxide scale following prolonged exposure. The high iron content of the test alloys had deleterious effects on the performance of these alloys in the environment.     

炉料搭配和均匀化处理对铸造锌铝合金组织与性能的影响

采用扫描电子显微镜和能谱微区分析,研究了以全新炉料和新旧炉料两种不同炉料搭配方式生产铸造锌铝合金铸件的组织与性能,并对其在铸态和经均匀化处理后的显微组织及成分进行了对比分析。发现采用全新炉料搭配比采用新旧炉料按1∶1搭配的铸造锌铝合金显微组织均匀、力学性能好;在相同条件下,经均匀化处理比铸造状态下的综合性能好。