Aluminum-magnesium-lithium alloys featuring low residual induced radioactivity and high electrical resistivity have been developed for fusion reactor structural materials. The addition of lithium in aluminum and Al-Mg alloys markedly increases electrical resistivity and tensile strength of them. However the elongation of Al-Mg-Li alloys containing more than 2 mass% lithium are less than 10%. The Al-4-5 mass%Mg-1 mass%Li alloys are optimum for fusion reactor materials, and exhibit high resistivity (86nΩm: 20%IACS), medium strength (300MPa) and good formability (22% elongation). The variation of electrical resistivity of Al-Li and Al-Mg-Li alloys in solid solution can be approximated by the Matthiessen's rule.
Al/FeS2 secondary cells have been investigated as a candidate of specific energy batteries. In this study, the organic electrolyte, i. e., n-butyl pyridinium chloride (n-BPC)-AlCl3, was used to get an adherent Al deposit and to operate the cell at around room temperatures. The cell with the electrolyte of [n-BPC]/[AlCl3]=1 had a high open circuit voltage of 2.5V, while in the case of other composition electrolytes the voltages were about 2.0V. Various additives to the FeS2 electrode were studied to improve the cell performance. The 45wt% graphite and 18mol% Cu2S additives were the most promising. The cells with Al alloys (5052, 6063, or Al-0.05%In) as the negative electrode also had the high voltage and high capacity. The cyclic voltammetry and the rotating ring-disk electrode measurements were performed to analyze the electrochemical reaction of the positive electrode. It was assumed that the intermediates, S2- and S2-n, are formed during the cathodic reaction of FeS2.
Cutting test were carried out for the two main groups in the cutting tests, one is regular type turning with a high speed steel tool and with a carbide tool, another is mirror finished cutting with a diamond tool. Cutting force was found rather low in the none Mg alloy and in 4.41% Mg alloy cutting when the cutting speed was higher than 2m/s and Mg content was more than 2.48% built up edge was almost disappeared. Chips disposal was improved slightly by containing Mg in the alloy. In the regular type turning, depth of affected layer of cut surface was decreased by increasing Mg content. On the other hand, affected layer of mirror finished surface was so small depth and the surface roughness (Rmax) of 0.02-0.03μm was generated in the mirror finished cutting of every kind of alloys in this test. Reflection factor of the mirror finished surface of rich Mg content was better than that of little Mg content.
Hydrogen embrittlement of 7075 specimens aged at 120°C for 1 hour, which were prepared to have various orientations, was investigated by a tensile test of cathodically charged ones. Hydrogen permeation behaviors for these specimens are similar to each other, but permeation from T or S plane of rolled alloy is seemed to be somewhat easier than that from L plane. Embrittlement of the specimens with S-L or S-T direction is observed to be more remarkable than that of the specimens with T-L or L-T direction, although the difference in hydrogen permeation behavior of these specimens is slight. Such anisotropy of hydrogen embrittlement can be explained by two concepts based on the differences caused by an anisotropic grain structure of the alloy; one is the normal stress componsnt on the grain boundary plane and the other is the degree of facility of hydrogen permeation. The details are discussed, and characteristic features in the fracture of embrittled specimens are also investigated.
Rolling tests are carried out to confirm if Orowan theory is applicable to hot rolling of aluminum. In some cases using lubricant, sliding friction with low friction coefficients occurs, on the other hand in cases without lubricant sticking friction occurs. On the whole, mixed sliding and sticking friction is dominant in hot rolling of aluminum. For the prediction of rolling force, precise estimation of rolling temperature is necessary, because temperature fall during rolling is over 100°C in some cases. Moreover, precise estimation of mean flow stress is also necessary, because it has variation over 10% even for the same materials according to the small deviation of chemical composition or heating condition in the soaking furnace etc. By considering the above, the calculated rolling force and forward slip agree well with the experimental ones with sufficient accuracy.
Relation between extruded aluminum surface structure and vacuum property was studied and the following results were obtained. 1) 6063 alloy extruded with the conditions of preventing air from entering inside of pipe and of taking in mixture gas of Ar+O2, showed low outgassing rate (2×10-13Torr•l/s•cm2) by only 150°C, 24h baking. And the inside of pipe showed pumping effect which is considered to adsorb gas molecules in space. 2) The material extruded in mixture gas of Ar+O2 by aluminum alloy of which magnesium is removed from 6063 alloy, showed the higher outgassing rate (1×10-12Torr•l/s•cm2) than that of 6063 alloy, in addition, showed no pumping effect. 1060 alloy extruded in mixture gas of Ar+O2 showsd the lower outgassing rate (7×10-14Torr•l/s•cm2), but showed no pumping effect. In this way, we could obtain new functional surface which has extremely low outgassing rate by controlling atmosphere in extrusion.