| Project/Area Number |
61550521
|
|---|
| Research Category |
Grant-in-Aid for General Scientific Research (C)
|
| Allocation Type | Single-year Grants |
|---|
| Research Field |
金属材料(含表面処理・腐食防食)
|
|---|
| Research Institution | YAMAGATA University |
|---|
Principal Investigator |
MATSUURA Keisuke YAMAGATA University, Professor, 工学部, 教授 (00001157)
|
|---|
| Co-Investigator(Kenkyū-buntansha) |
MATSUDA Norio YAMAGATA University, Research Assistant, 工学部, 助手 (00007220)
|
|---|
| Project Period (FY) |
1986 – 1987
|
| Project Status |
Completed (Fiscal Year 1987)
|
| Budget Amount *help |
¥2,100,000 (Direct Cost: ¥2,100,000)
Fiscal Year 1987: ¥900,000 (Direct Cost: ¥900,000)
Fiscal Year 1986: ¥1,200,000 (Direct Cost: ¥1,200,000)
|
|---|
| Keywords | Dispersion-Hardening / Short Fibre-Reinforcement / Mechanical Alloying / Creep / -Projection / θプロジェクション / クリープ変形 / 限界応力Al基複合材 / 組織制御 |
|---|
| Research Abstract |
CREEP TESTS WERE CARRIED OUT ON SOME DISPERSION-HARDENED Al-Al_4 C_3 SYSTEM ALLOYS AND SHORT FIBRA-REINFORCED Al-Al_2 O_3YLLOYS TO EXAMINE THE CREEP BEHAVIOR AND THE EFFECT OF HEAT TREATMENT ON IT. MAIN RESULTS ARE AS FOLLOWS:
1. Al-Al_4 C_3-4%Mg ALLOY(4.5 VOL.% DISPERSOIDS) AND Al-Al_4 C_3ALLOY(9 VOL.% DISPERSOIDS).
(1) THE MICROSTRUCTURE OF THESE ALLOYS CONSISTED OF VERY FINE SUBGRAINS OF ABOUT 0.4-0.8 <micrn>m WHICH WERE STABLE UP TO ABOUT 873K. AS THE ANNEALING TIME AT 823 K INCREASED FROM1h TO 24 h, THE SIZES OF SUBGRAINS AND DISPERSOIDS CHANGED ONLY BY ABOUT 20%, WHILE THE CREEP STRENGTH WAS APPRECIABLY DECREASED BY THE INCREASE OF ANNEALING TIME.
(2) CREEP CURVE SHAPE AND MINIMUM CREEP RATE WERE DRASTICALLY CHANGED WITH STRESS NEAR A CRITICAL STRESS. THE CREEP CURVE WAS MAINLY DOMINATED BY THE PRIMARY AND SECONDARY STAGES IN THE STRESS RANGE BELOW THE CRITICAL STRESS AND BY THE TERTIARY STAGE IN THE STRESS RANGE ABOVE IT.
(3) THE DECREASE OF CREEP STRENGTH BY INCREASE OF ANNEALING T
… More
IME WAS CAUSED FROM DECREASE OF THE CRITICAL STRESS, POSSIBLY DUE TO THE CHANGE OF DISLOCATION STRUCTURE IN SUB-BOUNDARIES. ON THE OTHER HAND, THE CRITICAL STRSS WAS ENHANCED BY PREVIOUS CREEP DEFORMATION AT STRESSES LOWER THAN THE CRITICAL STRESS, POSSIBLY DUE TO THE STRENGTHENING OF SUB-BOUNDARIES.
2. SHORT FIBRE-REINFORCED Al-Al_2O_3 ALLOYS(VOLUME FRACTION: 5, 10 AND 18%).
(1) THE ALLOYS WERE ANNEALED 2 h at 773 K. THE CREEP CURVE MAINLY CONSISTED OF THE TERTIARY STAGE IN THE LOW STRESS RANGE WHEARE THE INSTANTAMEOUS STRAIN WAS ONLY ELASTIC, WHILE THE PRIMARY STAGE WAS DOMINANT IN THE HIGH STRESS RANGE WHERE THE INSTANTANEOUS STRAIN HAD THE PLASTIC COMPONENT.
(2) <theta>-PROJECTION CONCEPT WAS SUCCESSFULLY APPLIED TO THE ANALYSIS OF CREEP CURVES. THE <theta>PARAMETERS PRESENTING THE RATE CONSTANTS OF PRIMARY AND TERTIARY CREEPS RESPECTIVELY, <theta>_2 AND<THETA>_4 WERE ABOUT EQUAL AND DETERMINED BY THE SELF DIFFUSION OF ALUMINUM.
(3) THE CREEP CURVE OR CREEP RATE WERE NOT AFFECTED BY THE VOLUME FRACTION OF FIBRES WHEN IT WAS LARGER THAN 10%. Less
|
