The effects of Sr,Mg,Cr,Sr/Mg and Sr/Cr combined additions on the Fe-containing intermetallic phase in a recycled Al-Si-Fe cast alloy are investigated.The experimental results show that the additions of Cr and Sr/Cr s...The effects of Sr,Mg,Cr,Sr/Mg and Sr/Cr combined additions on the Fe-containing intermetallic phase in a recycled Al-Si-Fe cast alloy are investigated.The experimental results show that the additions of Cr and Sr/Cr successfully modified the platelet and flake-likeβ-Al-5FeSi phases （β-compound） into the fibrousα-Al-8Fe-2Si （α-compound）.The additions of Sr and Sr/Mg were less effective to modify theβ-compound into theα-compound,while the eutectic Si was fully modified into the fibrous morphology.A small secondary dendrite arm spacing （DAS） was found in the Sr-added,Cr-added and Sr/Cr-added alloys,especially in a steel mold.The Sr,Sr/Cr and Sr/Mg combined additions modify the eutectic Si simultaneously.A sludge phase was found in the addition of Cr-added,Sr/Cr-added and Mg-added alloys,especially in the graphite mold casting.The volume fraction ofβ-compounds was decreased by the addition of various modifying elements. The Cr and Sr/Cr combined additions are very effective to modify theβ-compound for the recycled Al-Si-Fe based alloys.展开更多
本文开展了有机硅改性酚醛树脂复合材料制备及性能研究。首先进行有机硅改性酚醛树脂复合材料的制备:将4 g甲基苯基二甲氧基硅烷溶于25 m L四甲基氢氧化铵中,然后将得到的料液添至去离子水中进行搅拌,得到黄色固体,并将其置于60℃烘箱中...本文开展了有机硅改性酚醛树脂复合材料制备及性能研究。首先进行有机硅改性酚醛树脂复合材料的制备:将4 g甲基苯基二甲氧基硅烷溶于25 m L四甲基氢氧化铵中,然后将得到的料液添至去离子水中进行搅拌,得到黄色固体,并将其置于60℃烘箱中,设置时间24 h,得出有机硅改性酚醛树脂复合材料。再者,对有机硅改性酚醛树脂复合材料的热性能及复合材料层间剪切强度进行测试。研究结果表明:当固化环氧树脂和固化剂质量比为95∶5时,有机硅改性酚醛树脂复合材料性能最优,此时其层间剪切强度高达87.5 MPa,热失重质量为0.22 g,耐热性能更好。展开更多
文摘The effects of Sr,Mg,Cr,Sr/Mg and Sr/Cr combined additions on the Fe-containing intermetallic phase in a recycled Al-Si-Fe cast alloy are investigated.The experimental results show that the additions of Cr and Sr/Cr successfully modified the platelet and flake-likeβ-Al-5FeSi phases （β-compound） into the fibrousα-Al-8Fe-2Si （α-compound）.The additions of Sr and Sr/Mg were less effective to modify theβ-compound into theα-compound,while the eutectic Si was fully modified into the fibrous morphology.A small secondary dendrite arm spacing （DAS） was found in the Sr-added,Cr-added and Sr/Cr-added alloys,especially in a steel mold.The Sr,Sr/Cr and Sr/Mg combined additions modify the eutectic Si simultaneously.A sludge phase was found in the addition of Cr-added,Sr/Cr-added and Mg-added alloys,especially in the graphite mold casting.The volume fraction ofβ-compounds was decreased by the addition of various modifying elements. The Cr and Sr/Cr combined additions are very effective to modify theβ-compound for the recycled Al-Si-Fe based alloys.
