Sr含量对4004铝合金铸锭变质效果的研究

Study of Modification Effect of Sr Content on 4004 Aluminum Alloy Ingot

研究了Sr加入量分别为0.01%、0.015%、0.02%,变质保温时间分别为60min、80min、100min,对4004铝合金变质效果的影响。结果表明:Sr加入量低于0.015%、变质保温时间小于80min时,合金组织和力学性能均没有达到完全变质状态;Sr加入量0.015%、变质保温时间80min时,4004铝合金变质效果最好,合金组织中的初晶硅转变为细小的圆状或短棒状,共晶硅也由片状或针状转变为纤维状,合金的抗拉强度和伸长率达到最大值193MPa和4.2%;Sr加入量超过0.015%、变质保温时间超过80min时,随着加入量的增加,合金组织开始变得粗大,抗拉强度随着下降。

The paper highIighted modification effect of increasing Sr content （0. 01,0. 015,0. 02 wt %）on 4004 aI oy with increasing modification hoIding time （60,80,100min）.The resuIts indicated when Sr addition was beIow 0.015% and hoIding time was Iess than 80min,neither microstructure nor mechanicaI properties of the aI oy reached fuI y modified state;0.015%Sr addition and 80min hoIding time were best effective for the aI oy modification with uItimate tensiIe strength and eIongation of 193Mpa and 4. 2% respectiveIy,primary siIicon became gIobuIar or short rod-Iike and eutectic siIicon transformed to fibrous from fIaky or acicuIar in microstructure of the aI oy;excessive Sr addition and hoIding time resuIted in coarse grain and decIine of tensiIe strength.