Effects of Cu on impact strength of Al-Si alloys

Abstract

Effects of Cu on the impact strength and structures of Al-Si alloys were examined by mean s of Charpy impact test and metallographical method. The following three types of specimens were used: a) As cast. b) Solution heat treated at 500 °C for 240 min . for the above specimens. c) Artificially age hardened at 200 °C for 300 min. after the above solution heat treatment .(1) The impact strength of as cast alloys tended to be decreased with the increase in Si content and Cu addition. When Si content was low (approximately below 4%) , the strength was markedly decreased with the addition of Cu. However, the strength was gradually decreased with increasing Si content and no effects of Cu were seen on the strength at about 15% of Si content.(2) By the addition of a small amount of Cu to the hypo-eutectic alloy of nearly eutectic composition with no primary Si crystals, a marked decrease of the impact strength was seen on the specimens solution heat treated at 500 °C. The above decrease resulted from the formation of primary Si crystals due to the addition of Cu . The configuration of these primary Si crystals was the cause of stress concentration as reported in the previous paper,l~ and it was kept unchanged by holding at 500°C.(3) The impact strength of the alloys, which had been artificially age hardened at 200 °C after solution heat treatment at 500 °C, tended to be decreased with the increase in Si content and Cu additioon . Especially, the effect of Cu addition was greater than that of Si content. (Received Feb. 10, 1970)

Effect of additives on the mechanical properties and machinability of a new aluminum-copper base alloy /

“…The effects of iron on the mechanical properties of Al-Si casting alloys were investigated by Komastu et al 146 Their results show that iron has a detrimental effect on the impact strength of such alloys because of the formation of Al-Si-Fe compounds.…”

Effets du magnésium et des conditions de vieillissement sur la résilience des alliages Al-Si-Cu-Mg de type 319 /

“…14 Load-time relationship for $-notch and U-notch specimens. [65] The difference between the load-time curves for $-notch and U-notch specimens of Al-Si alloys, as observed in the work of Komatsu et a/., [65] is shown in Figure 2.14. The configuration of the $-notch specimens used in their study is shown in Figure 2 In view of the fact that unnotched samples were used in this study, higher impact energies were therefore expected to be obtained.…”

Effet des additifs sur la microstructure et les propriétés mécaniques des alliages d'aluminium-silicium /

“…Komastu et al 252 Their results show that iron has a detrimental effect on the impact strength of these alloys because of the formation of Al-Si-Fe compounds. Table 5.2 shows the results for the different parameters as determined from the instrumented impact tests for the Sr-modified grain-refined RGM alloy, thus making it possible to investigate the effects of various additions of Fe, whether individually or in combination with Mn, in as-cast and heat-treated conditions, hi the as-cast condition, the total absorbed energy, E t , of the RGM alloy is found to decrease with an increase in Fe whether added individually, or in combination with Mn.…”