Microstructure,mechanical properties and wear resistance of an Al–Mg–Si alloy produced by equal channel angular pressing

Microstructure, mechanical properties and wear resistance in an ultrafine-grained Al–Mg–Si alloy fabricated utilizing a combination of equal channel angular pressing (ECAP) and dynamic aging were investigated in this paper. The results indicated that the grain size of the ECAP alloy was significantly refined, i.e., to ~239 nm after three ECAP passes. Meanwhile, the yield and tensile strength of the ECAPed material reached 340 MPa and 445 MPa, respectively, while maintaining a significant uniform elongation of 14%. Wear resistance results demonstrated that the wear rate, wear depth and width of the ECAPed material decreased in comparison with the solution-treated (SST) and peak-aged (T6) conditions under a load range of 5–25 N. The adhesive wear that occurs in the undeformed specimens at 10 N does not appear in the ECAPed specimen at the same load, indicating that the ECAPed specimen delay the appearance of more serious wear mechanisms under certain loads. The cooperative interaction of high density nano-scale β" precipitates and dislocations resulted in a combination of super-high strength and good work hardening ability which suppressed the extension of cracks between the friction layer and the plastic deformation zone. As a consequence, the combination of ECAP and dynamic aging brings a significant improvement for antifriction performance of the 6061 aluminum alloy.     

多级Nd－Fe－B强永磁体悬挂带式除铁器的研究

利用Ｎｄ—Ｆｅ—Ｂ强永磁合金研制成多级悬挂带式除铁器，其综合性能优于目前国内外使用的电磁铁和铁氧体型除铁器，具有磁力强、轻便及除铁效果好等特点。     

The hidden disintegration of cluster heterogeneity in Fe-based glass-forming alloy melt

The evolution of liquid metal at high temperature is known much less than their solid states. This is partially due to that the message concerning clusters, metastable phase or heterogeneity in liquid is usually too slight to be traced. Here, we shed some light on the nature of structural evolution of Fe-based glass-forming alloy during overheating process by the investigation of high-temperature melt viscometry and first principles simulations. It was found that a structural transition around 1400 ℃ occurred in the melts of initial homogeneous ingot, heterogeneous ingot and amorphous ribbons jointly, and was confirmed by the results from differential scanning calorimeter(DSC), and ab initio molecular dynamics(AIMD). Combining these results with Fe-Si-B ternary phase diagram and the melting characteristics of Fe-B compounds, it is safe to conclude that the disintegration of Fe_2B type clusters to Fe_3B-type clusters leads to the observed transition. These results offer a significant reference for the preparation and property control of Fe-based amorphous alloys.     

关于铝合金材料性能的论述

介绍多种铝合金材料及相关成型方法,性能,用途,优缺点,广阔前景。着重介绍2004年日本制钢所由纳米微细结晶粒构成的锌铝合金的性能和实用前景。     

Kondo合金低温电阻率的自洽计算

从Slave-boson平均场理论出发,对Yoshimori-Kasai模型进行修正,应用相干势近似(CPA)方法计算了Kondo合金低温电阻率。结果表明,当合金中磁性原子浓度大于某个值时,重费米子系统明显地表现出相干性。给出了低温下电阻率的表达式。     

非晶态Ni-P合金的组织结构转变

本文采用化学镀方法制备非晶态Ni-P合金,研究了非晶态Ni—P合金的组织结构转变过程。结果表明,非晶态Ni-P合金的磷含量影响其晶化转变,磷含量小于11.0％,晶化相为f.c.c Ni,大于11.0％的则为Ni_3P,其过程类似过冷液体的结晶过程。     

强烈机械搅拌对Al－Cu10％合金结晶方式的影响

分析了强烈机械搅拌作用对Ａｌ－Ｃｕ１０％合金结晶组织的影响。指出强烈机械搅拌作用下形成的粗大玫瑰状组织和无分枝的颗粒状晶体是由于强烈机械搅拌作用导致液固界面前方形成很薄的溶质原子富集层，使得晶体平面生长，并在生长过程中分枝以粘合方式粗化的结果。     

超塑性与耗散结构

以Ｚｎ－５Ａｌ合金为例，从能量观点出发对其超塑性进行了研究，结果表明，其超塑性拉伸延伸率达５００％，其低抗力、无颈缩、均匀变形能力表明了变形过程协调的高度有序性──耗散结构，其本质是系统自由能的平衡过程。     

钯铁合金镀液和镀层中钯和铁的同时测定

在酸性介质中，铁和钯分别与亚硝基Ｒ盐（ＮＲＳ）络合形成绿色的Ｆｅ－ＮＲＳ和红色的Ｐｄ－ＮＲＳ．利用它们的吸收光谱性质的差异，可用双波长系数法在水相中同时测定Ｆｅ和Ｐｄ．实验证明，两络合物的摩尔吸光系数分别为１．９４×１０４（对铁）和１．６３×１０４（对钯），线性范围分别为０～６０μｇ／ｍＬ和０～７０μｇ／ｍＬ，相对标准偏差小于０．５％，回收率为９６％～１０５％．本方法简便、快捷、准确、重现性好．适用于合金镀液及镀层中铁和钯的同时测定．     

金属表面合金化的研究

Rh(001),(111)和(111)表面被Mo合金化的原子绪构已首次成功地用场离子显微镜直接观察到。表面合金化是采用在超高真空系统中气相沉积及随后淬火,低温扩散来实现。交换机制是可能的扩散机制。观察到的环状结构是Rh-Mo合金中Mo原子优先场蒸发造成的。