Effect of cooling rates of production process of Al-3%B-3%Sr master alloy on grain refinement and eutectic modification efficiency in cast A356 alloy

Abstract

Abstract. In this paper, size and morphology of the grain refiner and modifier particles in the Al-3%B-3%Sr master alloy production by using different cooling rates were investigated. Two Al-3%B-3%Sr master alloys were produced with 0.2 and 10°C/s, respectively. The grain refinement and eutectic modification efficiency of the Al-3%B-3%Sr master alloy were tested in casting process of A356 alloy by addition of 4wt.% and holding times for 10-120 min. The experimental result showed that microstructure of the M1 alloy (Slow cooling) consisted of larger solidified particles of AlB2, SrB6 and Al4Sr in the matrix of α-Al compared to the M2 alloy (Rapid cooling). The addition of the M1 alloy in cast A356 alloy, it was found that small grain size and fully modify eutectic silicon were obtained from the holding time in a range of 10-60 min. While the addition of M2 alloy, a small grain size was achieved in shorter holding time in a range of 10-30 min but the eutectic silicon was partly modify. From the thermal analyzed result, solidification of un-modified A356 alloy was changed after addition of Al-3%B-3%Sr master alloy. It was clearly observed that both the undercooling of nucleation and eutectic reaction was reduced and the solidification time was shifted to longer.

Effect of chromium content on microstructure and properties of casting Al‐7Si‐0.35Mg‐0.02Sr alloy

“…Generally, to produce A356, 0.3 %-0.45 % of magnesium is added to the common Al-7Si alloy, followed by T6 heat treatment to precipitate dispersed magnesium silicide nanoparticles for significant performance improvements [2,3]. Recently, research on A356 is focused on performance improvements via multi-element microalloying and the subsequent heat treatment processes [4][5][6][7][8]. Meanwhile, rare earth elements, such as erbium, lanthanum, scandium, cerium, and europium, have been studied extensively [9][10][11][12][13].…”

Archives of Metallurgy and Materials

“…The grain refinement and eutectic Si modification are widely used to improve their microstructure and mechanical properties of al-Si cast alloys [1][2][3][4][5][6]. normally, the addition of conventional master alloy such as the al-Ti, al-Ti-B or al-B and combinations between grain refiner and modifier alloy system such as al-Ti-B-Sr, al-Ti-C-Sr and al-B-Sr [7][8][9][10][11][12][13][14][15][16]. These combined master alloys allow for easier control of chemical composition compared to conventional additions.…”