LAUSR

In current research, the interactive effects of different parameters such as melt overheating temperature, the location of gating system and incorporation of the grain refiner in bar and micro-powder form on the mechanical and structural characteristics of commercially pure aluminium are examined. Results show that increasing the melt temperature as well as employing a gating system with higher heat transfer rate increases the ultimate tensile strength (UTS) of the pure aluminium by 7%. Also, the introduction of 2wt% Al–5Ti–1B grain refiner in bar form into the overheated melt enhances the UTS values by two times, while incorporating 2wt% Al–5Ti–1B grain refiner in micro-powder form leads to achieving 32% higher UTS compared to the samples with grain refiner in the bar form due to the elimination of Al3Ti brittle phase, as confirmed by XRD patterns and SEM fracture surface images.摘要本文研究了熔体过热温度、浇注系统的位置、棒状和微粉状晶粒细化剂等不同参数对纯铝力学 性能和结构性能的影响。结果表明,提高熔体温度和采用高传热率浇注系统将纯铝的极限拉伸强度提 高了7%。此外,在过热熔体中引入2 wt% Al–5Ti–1B 棒状晶粒细化剂,可使合金的极限拉伸强度提 高2 倍。通过XRD 和断口形貌分析发现在合金中加入2 wt% Al–5Ti–1B 微粉状晶粒细化剂,可以消 除Al3Ti 脆性相,从而提高其极限拉伸强度,比加入棒状晶粒细化剂的合金高32%。