Journal of Japan Institute of Light Metals
Online ISSN : 1880-8018
Print ISSN : 0451-5994
ISSN-L : 0451-5994
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Volume 47, Issue 6
Displaying 1-8 of 8 articles from this issue
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RESEARCH REPORT
  • Drilling of Al–17%Si alloy (T6 treated) with the coated and carbide drills
    Liming SUN, Hisakimi NOTOYA, Shigeru YAMADA, Noboru TAKANO, Tatsuo OYA ...
    1997 Volume 47 Issue 6 Pages 311-316
    Published: 1997
    Released on J-STAGE: March 30, 2007
    DOIhttps://doi.org/10.2464/jilm.47.311
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    The drilling performance of the hyper-eutectic Al–17%Si–T6 extruded alloy was investigated by using cermet drill, cemented carbide drill, and cemented carbide drills coated with diamond layer, TiN single-layer and Ti–C–N multilayers. The drilling experiment was conducted with a CNC drilling center (step less drive) by changing machining parameters under a wet condition. The effect of coating material for the various drills on the drilling performance are discussed and evaluated to examine the tool wear, drilling force, chip form and height of burr. The main results are as follows: (1) The wearing behavior of diamond coated drill was very stable for the range of experimental parameters and its tool life is 100 times longer than the others. Therefore, it can be considered that the diamond coated carbide drill is one of the most realistic tool for drilling the hyper-eutectic Al–Si alloys. (2) The wearing behavior of drills, except diamond coated carbide tool, changed with incresing cutting speed and the flank wear of carbide drill was least at the high cutting speed (>1.1 m/s). (3) The cutting speed influences more remarkably on the chip form than the feed rate. The difference of drills is found to have no influence on the chip form. (4) Burr height on entrance circumference corner of drilled holes corresponded to the flank wear of drill; therefore it is affected by cutting conditions and the difference of drills.
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  • Preparation of hardened Ti(C, N) layer by plasma carbonitriding of Ti
    Takayasu SATO, Shigeru ITO, Kazuo AKASHI
    1997 Volume 47 Issue 6 Pages 317-322
    Published: 1997
    Released on J-STAGE: March 30, 2007
    DOIhttps://doi.org/10.2464/jilm.47.317
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    Plasma carbonitriding process has been applied to preparation of hard Ti(C, N) layer on the surface of titanium plate at relatively low temperatures. The formation of thick Ti(C, N) layer was confirmed by means of XRD and ESCA measurements and Vickers hardness test. The carbonitriding was carried out in an r.f. (4 MHz) glow plasma generated in quartz tube using N2–C2H2 gas mixtures. The Ti(C, N) layer consisted of continuous solid solution of TiN and TiC. With increase in the C2H2 ratio of carbonitriding gas, the thickness of carbonitriding layer somewhat decreased, but the friction coefficient of the surface was improved and its value was similar with that of commercial TiN films for cutting tools. The addition of inert gas (He, Ar) into N2–C2H2 gas somewhat decreased the thickness of the carbonitriding layer, while the surface roughness of carbonitrided Ti was rather improved. It may be presumed that the bombardment of massive inert gas ion assists to make the surface more smooth.
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  • Warm deep drawability with hydraulic counter pressure of 1050 aluminum sheets
    Kazuhiko NAKAMURA
    1997 Volume 47 Issue 6 Pages 323-328
    Published: 1997
    Released on J-STAGE: March 30, 2007
    DOIhttps://doi.org/10.2464/jilm.47.323
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    As a forming method for improving the limit of deep drawing, a warm deep drawing process with hydraulic counter pressure, which is the combination of warm deep drawing process and hydraulic counter pressure deep drawing process, is proposed. As for this forming method, the improvement of limiting drawing ratio can be expected through the control of work hardening by heating flange part and the prevention of fracture by pressing the formed side wall to a punch with hydraulic pressure. According to the experiment up to the forming temperature of 200°C, by controlling the highest hydraulic pressure so that the fracture due to excessive bulging deformation does not arise, and by forming at the forming speed of 3 mm/s or less, it is successful to improve the limiting drawing ratio of A1050–O material up to D0 max/dp=3.40 in cylindrical cups and D0 max/lp=3.59 in square cups. However, at the forming temperature of 200°C, the flange part of H24 material was softened, and the improvement of its limiting drawing ratio has not been attained. Moreover, it is elucidated also that when the warm forming of H24 material is carried out, strain figures and flow marks arise, and the surface properties of the formed products are deteriorated.
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  • Microstructure formation process and grain refinement of heptane added Ti–Al mechanically alloyed powders
    Toshinori FUJII, Satoru SODEOKA, Kei AMEYAMA
    1997 Volume 47 Issue 6 Pages 329-336
    Published: 1997
    Released on J-STAGE: March 30, 2007
    DOIhttps://doi.org/10.2464/jilm.47.329
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    Microstructure formation process during heating of n-heptane added mechanically alloyed (MA) Ti–Al compacts, as well as the effects of aluminum content and heating rate on the grain refinement of the MA compacts whose compositions were Ti–33~53 mol%Al were investigated. Aluminum supersaturated α nanocrystals were formed in Ti-rich Ti–Al powders, while the mixture of an amorphous phase and aluminum supersaturated α nanocrystals was formed in the MA powders with the aluminum contents more than 49 mol%. TEM/EDS examination of Ti–41, 46 and 51 mol%Al MA powders revealed that the α phase in the MA powders underwent a massive transformation to a non-equilibrium γ phase at the heating between 873 K and 973 K. In the case of Ti–51 mol%Al MA powder, crystallization of the amorphous phase to an α phase took place prior to the massive transformation. In the case of Ti–46 mol%Al MA powder, higher heating rate yielded finer grain size due to the finer dispersion of Ti2AlC particles. Increase in aluminum content resulted in the finer grain microstructure because of the increase in Ti2AlC particles in the vacuum hot pressed compacts sintered at 1173 K for 3.6 ks. Thus, grain refinement in the Ti–Al MA compacts can be accomplished by controlling the heating rate and the aluminum content.
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  • Improvement in fit of sealed anodized coating of aluminum at friction and abrasion
    Masatsugu MAEJIMA, Koichi SARUWATARI, Matsufumi TAKAYA
    1997 Volume 47 Issue 6 Pages 337-340
    Published: 1997
    Released on J-STAGE: March 30, 2007
    DOIhttps://doi.org/10.2464/jilm.47.337
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    The effects of sealing treatment on the mechanical properties, such as friction and abrasion properties of anodized coatings were studied. Sealing treatment has not been regarded as important for the improvement of mechanical properties of anodized coatings, because sealing brings about occasional softening of films and occurrence of cracks. The following results were obtained: (1) Boiling water sealing for about 30~45 minutes improves wettability with lubricant and initial familiarity, and as the result friction force and wear traces get smaller. (2) Wetting of anodic oxide films with lubricant by capillary attraction depends heavily on the viscosity and surface tension of the lubricant. Wettability gets improved as these get smaller.
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  • The modification of microstructures and mechanical properties of JIS AC3A alloys by dephosphorising
    Naoto OSHIRO, Takao SUZUKI, Eiji KATO
    1997 Volume 47 Issue 6 Pages 341-346
    Published: 1997
    Released on J-STAGE: March 30, 2007
    DOIhttps://doi.org/10.2464/jilm.47.341
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    The effect of phosphorus on microstructure and mechanical properties of dephosphorised JIS AC3A alloys was investigated. In 3 ppm phosphorus alloy, eutectic silicon crystallizes in very fine and lamellar structure, and iron base intermetallic compounds crystallizes in very fine one. In case of 12 ppm phosphorus alloy, eutectic silicon takes a coarse acicular shape, and iron base intermetallic compounds are also coarse. Strength of 3 ppm phosphorus alloy is larger than that of 12 ppm phosphorus one. Particularly elongation and absorbed energy of 3 ppm phosphorus alloy are over three times as large as those of 12 ppm phosphorus alloy. By dephosphorising commercial alloys, we removed the deleterious effect of phosphorus on microstructure of eutectic silicon and iron base intermetallic compounds and improved mechanical properties.
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  • Dynamic strength of friction welded joint of 6061 aluminum alloy to SUS304 stainless steel
    Hiizu OCHI, Koichi OGAWA, Yoshiaki YAMAMOTO, Yasuo SUGA
    1997 Volume 47 Issue 6 Pages 347-351
    Published: 1997
    Released on J-STAGE: March 30, 2007
    DOIhttps://doi.org/10.2464/jilm.47.347
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    Destructive test of the joints was carried out for examining the impact and fatigue strength. The softened area of A6061 side of the joints welded under a higher upset pressure is narrower compared with that welded under a lower upset pressure, because the softened area of A6061 side was expelled as the upset burr by the action of upset pressure. The dynamic strength of the joints depends on the width of the softened area of A6061 side. In the case of smoothed impact specimen, the impact absorbed energy of the joints increases with increase in upset pressure, while it decreases with the upset pressure over 240 MPa. On the other hand, no smoothed specimens of A6061 base material fracture. In the case of notched specimen, the impact absorbed energy of the joints welded under the upset pressures over 160 MPa remains to be almost equal to the maximum value, and the maximum joint efficiency is about 15%. The impact fracture occurres both in the mixed area of the weld interface and in the softened A6061 area. The fatigue strength at a given endurance (number of cycles to failure 107) of A6061 base material and the joints welded under 120 MPa and 240 MPa upset pressure are 121 MPa, 112 MPa and 122 MPa, respectively. The fatigue fracture of the joints occurres in the softened A6061 area or in the mixed area of the weld interface and the softened A6061 area depending on the welding conditions.
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RESEARCH NOTE
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