High temperature creep characteristics of Al-6.3at%Mg alloys containing small additional elements
スポンサーリンク
概要
- 論文の詳細を見る
The effects of small amounts of an additional element (Ag, Si or Zn) on the creep characteristics of Al-6.3at% Mg alloys were investigated for the specimens which had been subjected to two kinds of heat-treatments.The heat-treatment (A) was an attempt to obtain dispersed coarse particles. The specimens were solution heat treated at 400°C for 1hr. and furnace-cooled to 250°C at a cooling rate of 25°C/hr. Then, they were maintained at that temperature for 6 days and water quenched.The heat-treatment (B) was to produce dispersed fine particles by much nucleation. The specimens were solution heat treated at 400°C for 1hr. and water quenched. Then, they were maintained at 150°C for 2 days, at 200°C for 2 days, and at 250°C for 6 days, and then again water quenched. The heat treatments had remarkable effects on the creep characteristics such as activation energy (Q) and stress exponent (n) expressed in the following state equation of steady creep;εs=Aσnexp(-Q/RT)The activation energy (Q) and the stress exponent (n) for the creep at 250°C of the specimens heat-treated by (A) method were about 37kcal/mol and about 3, respectively. These values were approximately equal to those of Al-4.4at%Mg solid solution alloys. On the other hand, the activation energy and the stress exponent for the specimens heat-treated by (B) method were 2731kcal/mol and about 4 respectively, under the same testing conditions. The rate controlling step of the former treatment (A) would be the dragging of solute atmospheres around the jogs in screw dislocations and that of the latter treatment (B) would be due to the cross slip of dislocations. The difference between the effects of both treatments would be attributed to the change in transition temperature range from the cross-slip mechanism to the vacancy controlling mechanism.The three kinds of additional elements had little effects on the high temperature creep characteristics of Al-6.3at%Mg alloys. It would be attributed to the fact that the additional elements had been dissolved in β phases of Al-Mg alloys during the heat treatments before the creep.
- 一般社団法人 軽金属学会の論文
一般社団法人 軽金属学会 | 論文
- Mechanical and wear properties of SiC whisker/ADC12 aluminum alloy composites fabricated by die casting.
- Joining of aluminum and ceramics.
- タイトル無し
- Undercooling and solidification behavior of fluid clumps of second-poured melt of hypereutectic Al-Si alloy in Duplex Casting process.
- Change in apparent viscosity of stirred slurry during production of semi-solid hypereutectic Al-Si alloy by slurry-melt mixing process.