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Volume 36, Issue 12
Displaying 1-11 of 11 articles from this issue
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Masao KANEKO1986 Volume 36 Issue 12 Pages 789-790
Published: December 30, 1986
Released on J-STAGE: July 23, 2008
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Eiji KATO, Yoshisada UEDA, Hideshi MORI1986 Volume 36 Issue 12 Pages 791-798
Published: December 30, 1986
Released on J-STAGE: July 23, 2008
JOURNAL FREE ACCESSRelationship between the microstructure and the fracture toughness of high purity Al-Zn-Mg alloys, to which the Zr and Cr were added changing the quantity, was investigated. Adding the Zr content, it is observed that the grain size becomes smaller and the fracture toughness becomes bigger as the increased quantity. But as for the fracture toughness, it's maximum is seen when the Zr content is added with 0.18%. This is why, in case of Zr content is little in quantity, recrystallization is not controlled and the grain size becomes large, consequently the concentration in grain boundary localization occurs and it gives a intergranular fracture. In case of the addition more than 0.18% Zr, the distributive density of η' phase becomes low as soon as the large dispersoids appears in the matrix, and the fracture toughness decreases. As for the Cr content, the tensile strength falls in accordance with the increase of the added quantity, but the fracture toughness increases up to 0.32%. Because of the prior precipitating of η phase in the Cr despersoid uniformly in matrix. In comparison with Zr and Cr content, Zr content is superior to Cr content on the tensile strength. On the other hand, Cr content is superior to Zr content on the absorbed energy.View full abstractDownload PDF (3390K) -
Kinji SATO1986 Volume 36 Issue 12 Pages 799-805
Published: December 30, 1986
Released on J-STAGE: July 23, 2008
JOURNAL FREE ACCESSThe hole expanding tests of Al-sheets are carried out with flat punchs as a method for formability evaluation of flow-drill operation. A hydraulic testing machine with capacities 3 tons is designed, manufactured and used for experiments. The materials used for experiments are aluminum sheet 0 and H24, with sheet thickness 1.0, 1.5, and 2mm. Test pieces are disc blank which has concentric hole, and outer diameters 78, 70, and 60mm, inner diameter varied with conditions. As the results of the experiment, basic data for Al-sheet was obtained.View full abstractDownload PDF (2058K) -
Osami SERI, Kohsuke TAGASHIRA1986 Volume 36 Issue 12 Pages 806-812
Published: December 30, 1986
Released on J-STAGE: July 23, 2008
JOURNAL FREE ACCESSAttempts have been made to clarify the experimental evidence of the effects of manganese in Al-Mn alloys in 0.1M NaCl solution at romm temperature. From electrochemical mesurements it was found that pitting potential of pure aluminum was shift to slightly noble as containing Mn (II) ion (0.01M MnCl2). Cathodic polarization resistance of Al-Mn alloys increased with increasing immesion period into NaCl solution. The results of cathodic polarization curves and weight loss are explained in terms of Mn/Fe ratio in Al-Mn alloys.View full abstractDownload PDF (1395K) -
Yasuhiro OSAME, Katsusaburo TOYODA, Yoshishige TSUMURA, Muneo SUZUKI, ...1986 Volume 36 Issue 12 Pages 813-818
Published: December 30, 1986
Released on J-STAGE: July 23, 2008
JOURNAL FREE ACCESSThe sludge deposition of JIS die casting alloy ADC12 in the holding furnace was studied. A quaternary intermetallic compound (FeMn)3Si2Al15 deposits in the molten metal free from Cr. Critical Fe and Mn concentrations for sludge deposition at a holding temperature T°C are expressed as:
%Fe+{3.34-(T-630)/714}%Mn=2.39+(T-630)/152
A quinary Al-Si-Fe-Mn-Cr compound (FeMnCr)3Si2Al15 deposits in the molten metal containing Cr. Critical concentrations of Mn and Cr in molten ADC12 alloys containing 1.0% of Fe at a temperature T°C are expressed as:
%Mn+{4.00+(T-630)/333}%Cr=0.40+(T-630)/500View full abstractDownload PDF (1431K) -
Toshimi YAMANE, Yoshiki MASUGATA, Keiichi HIRAO1986 Volume 36 Issue 12 Pages 819-824
Published: December 30, 1986
Released on J-STAGE: July 23, 2008
JOURNAL FREE ACCESSTensile tests and transmission electron microscope observations were performed on pure aluminum finely grained by rapid solidification. Experimental results obtained are as follows,
1) Aluminum specimens of the average minimum grain size 2.9μm are obtained by rapid solidification on single roll. The cooling rate of these specimens is estimated 3×106K/s.
2) The yield stress and fracture elongation of finer grain specimens rapidly solidified are higher in tensile tests.
3) There is Hall-Petch relation between grain size and yield stress. Comparing to recrystallized aluminum, the yield stress of rapidly solidified aluminum is higher. σ0 and ky of rapidly solidified aluminum in Hall-Petch relation are 14.6MPa and 2.1MPamm1/2, and those of the recrystallized are 10.4-8.5MPa and 1.8MPamm1/2.
4) In a transmission electron microscope observation, tangling of dislocations, adhesion of dislocations to grain bounderies, secondery defects are observed. They are considered to be causes of higher yield stress of rapid solidified aluminum.View full abstractDownload PDF (1877K) -
Motohiro KANNO, Kazuhiro ITOI1986 Volume 36 Issue 12 Pages 825-829
Published: December 30, 1986
Released on J-STAGE: July 23, 2008
JOURNAL FREE ACCESSSpecimens of Al-4%Cu and Al-4%Cu-1.60Mg alloys were solution-treated at 500°C in a salt bath, or in an air furnace filled with water vapor generated at 100°C. After the solution-treatment followed by quenching, they were aged at temperatures ranging from 50 to 200°C and then subjected to electrical resistivity measurements and TEM observations. The aging rate of the Al-Cu alloy specimens solution-treated in water vapor was higher at 150-200°C and lower at 50°C than that of specimens solution-treated in salt. These phenomena were explicable based on the difference of secondary defect structures; coarse dislocation loops were formed in the case of salt and fine voids, in the case of water vapor. In contrast to this, no difference in the aging behavior was observed in Al-Cu-Mg alloy between two solutiontreating conditions, because secondary defects were commonly coarse dislocation loops in both cases. It was suggested that hydrogen formed by the decomposition of water vapor would stabilize void structure and that the interaction between hydrogen and magnesium atoms might reduce the above stabilizing effect.View full abstractDownload PDF (1734K) -
Chuji KAWAMURA1986 Volume 36 Issue 12 Pages 830-836
Published: December 30, 1986
Released on J-STAGE: July 23, 2008
JOURNAL FREE ACCESSTo apply partial extrusion to producing a projection bosses are used for fastening of the lap joints. The object of the present investigation is to provide reasonable answers to the effects of protrudeability and staking shapes of the bosses on the joint strength. As a result of the experiments, to perform the reliable staking operation is required to make preparations for the heigher boss height. This expection can be achieved by making the punch is tapered and a top section has a larger diameter than the boss diameter. As regards to the effect of flat and cross-point staked shapes on the joint strength, in cases of shorter the boss height and/or thinner the counterpart sheet to not become marked. But, there is make a difference in joint strength between the two in company with heigher the boss height, the firm joint during the flattening operations are obtained. However, staking shapes depending on the quality of the hole edge in the counterpart sheet, those things in accordance with edge coining becomes a very useful method.View full abstractDownload PDF (778K) -
Koichi OHORI1986 Volume 36 Issue 12 Pages 837-840
Published: December 30, 1986
Released on J-STAGE: July 23, 2008
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Masujiro HAYAMA1986 Volume 36 Issue 12 Pages 841-850
Published: December 30, 1986
Released on J-STAGE: July 23, 2008
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Ryohei TANAKA1986 Volume 36 Issue 12 Pages 851-860
Published: December 30, 1986
Released on J-STAGE: July 23, 2008
JOURNAL FREE ACCESSDownload PDF (1469K)
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