|Budget Amount *help
¥2,900,000 (Direct Cost : ¥2,900,000)
Fiscal Year 1998 : ¥600,000 (Direct Cost : ¥600,000)
Fiscal Year 1997 : ¥2,300,000 (Direct Cost : ¥2,300,000)
In the present study, in order to elusidate the mechanical characteristics of ultra fine-grained copper having the grain size of 200nm(UFG 0.2), indentation tests and scratch tests were carried out with a diamond pyramidal indenter.
And also, sliding wear tests of pin-on-disc type were carried out. Another four kinds of material, (1)UFG copper annealed at 473K, (2), (3)Po1ycrystalline copper of which grain size is l5mum and 700mum(CG), and (4)single crystal copper were tested in the experiments. The following conclusions were obtained.
(1) The rate of elastic recovery and the energy to produce a unit volume of indent are the greatest in UFG materials, medium in polycrystals and the smallest in single crystal.
(2) In the indentation creep test in the range of 5 to 400ksec., the longer the loading period, the smaller the indentation hardness of UFG materials is. On the other hand, the hardness of polycrystals and single crystals is not affected with loading period.
(3) Ratio of scratch hardness to indentation hardness of UFG is smaller than unity and those of polycrystals and single crystals are larger than unity.
(4) In both materials UFG 0.2 and CC, the severe and mild wear process were observed in the present experimental conditions, In the severe wear process the reciprocal transitions of the worn particles are observed between the contacting surface, On the other hand, in the mild wear process, the creation of the oxide particles and its growth and accumulations are observed.
(5) Wear of UFG 0.2 is greater than that of CC in all present experimental conditions. wear rate has a tendency of decrease with an increase of sliding speed, but it takes a peak magnitude at a specific sliding speed.