著者

土屋 大樹 牧田 悠暉 李 昇原 才川 清二 池野 進 松田 健二

出版者

一般社団法人 軽金属学会

雑誌

軽金属 (ISSN:04515994)

巻号頁・発行日

vol.71, no.4, pp.166-170, 2021-04-15 (Released:2021-05-15)

参考文献数

18

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Al-Si-Mg alloys have good castability and high strength can obtained by aging heat treatment. There are some reports about the age-hardening behavior of these alloys. However, the effect of additive elements on the age-hardening behavior with microstructure evolution in Al-Si-Mg alloys is not totally clarified yet. In the previous work, the effect of T5 heat treatment for age-hardening behavior and microstructure evolution in AC4C cast alloy were investigated. Fine rod-like precipitates which were reported in Al-Mg-Si alloy were observed near eutectic Si phase in AC4C alloy. Rod-like precipitates became coarser toward the center of α-Al dendrite. In this work, high purity AlSi-Mg alloys were fabricated, and the microstructure of the alloys in T5 condition was investigated by transmission electron microscopy (TEM). In Al-7%Si-0.4%Mg (mass%) alloy aged at 473K for 7.2ks, lots of needle-like precipitates, which were identified as β'' phase, were observed near the eutectic Si phase. On the other hand, rod-like precipitates and granular precipitates were observed far from the eutectic Si phase. Based on SAED patterns obtained from the rod-like precipitates and granular precipitates, Those precipitates were identified as Type-A precipitates and Si phase, respectively.

著者

池野 進 片山 暢 松田 健二 蓮覚寺 聖一 品川 不二雄 上谷 保裕

出版者

一般社団法人 軽金属学会

雑誌

軽金属 (ISSN:04515994)

巻号頁・発行日

vol.48, no.4, pp.179-184, 1998 (Released:2007-03-30)

参考文献数

9

被引用文献数

1 1 1

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Al–1.0 mass%Mg2Si–0.34 mass%Si alloy specimens which had been aged at 423 K for various times were tensile tested at room temperature. Changes in local deformation near grain boundaries with aging time were investigated by scanning tunneling microscopy. When a little loss in elongation occurred at early stage of aging, the folds generated at the grain triple junction. But they were very ambiguous and did not develop with increasing amount of deformation. The fold formations were difficult to be explained by the maximum resolved shear stress on a grain boundary plane (Fmax). If the elongation appreciably decreased and intergranular fracture began to occur with the progress of aging, the folds developed and became more clear. The fold formations at this stage could be explained by the Fmax in many cases. Frequencies of fold formations increased with the aging time over a range of under-aged to peak-aged condition, and this correlated approximately to the decrease in elongation. Even if the elongation considerably recovered in the specimen which had been aged at 473 K up to over-aged condition, the frequency of fold formation was similar to that of the peak-aged condition. In this case, however, two types of folds which had developed largely or had developed scarcely with the progress of deformation were observed and the frequency of the former ones decreased to about a half of the all folds.