Development of Aluminum Recycling Technology

这项研究的目的是寻找一种有用的元素来去除杂质，如Bi， Si， Fe等。期望在回收铝合金时混合，并用于确定杂质的公差极限，以满足JIS规定的变形Al-Mn和Al-Mg-Si合金的各种性能。从金相角度研究了再生铝合金的凝固行为以及杂质对其力学性能、成形性和耐蚀性的影响。(1)在6061和6063铝合金熔体中加入三维过渡元素V和Mn，形成尺寸大于10 μ m的巨型金属间化合物结晶。这些化合物是al - 6mn或α -Al (Mn, Fe) Si相，被其他元素取代，占据了它们晶体结构中Mn和Fe的位置，由于它们比铝熔体的比重大，它们在短时间内沉降在坩埚底部。(2)在Al-Mn（3003）中，随着Bi和Ca含量的增加，合金的抗拉强度和0.2%抗应力没有变化，但伸长率、夏比冲击值、成形性和耐蚀性下降。特别是，随着Ca含量的增加，CaAl_2Si_2化合物的粗大增加，导致伸长率和冲击值急剧下降。因此，3003合金中Ca的残留量应小于0.1%。(3)随着V、Mn、Ca含量的增加，Al-Mg-Si（6061）合金的抗拉强度和0.2%抗应力明显降低。这些化合物中含有大量的硅，这有助于6061铝合金的时效硬化。由于含v合金中粗大化合物的存在，伸长率和冲击值下降；在含锰合金中无变化；由于基体相的软化和含钙合金中精细分布的化合物而升级。Zr含量不超过0.3%时，对6061铝合金的各项性能没有影响。要求6061铝合金中V、Mn、Ca的含量分别小于0.2%、0.4%、0.1%，才能保证拉伸性能满足JIS标准。少

This study was conducted for the purposes of searching a useful element for the removal of impurities such as Bi, Si, Fe ets. expected to be mixed when recycling aluminum alloys and for determining the tolerance limits of impurities satisfying various properties of the wrought Al-Mn and Al-Mg-Si alloys specified by JIS.Solidification behavior, and effects of impurities on mechanical properties, formability and corrosion resistance of the recycled commercial aluminum alloys were investigated from the view point of metallography. (1) Giant intermetallic compounds with sizes of over 10 mu m crystallize when 3d transition elements such as V and Mn are added to 6061 and 6063 aluminum alloy melts. The compounds are Al_6Mn or alpha -Al (Mn, Fe) Si phases replaced by other elements on occupying sites of Mn and Fe in their crystal structures and they settle at the bottom of the crucible during a short time due to their larger specific gravity than that of aluminum melt. (2) In Al-Mn (3003) allo … More y, increases in contents of Bi and Ca cause no changes of tensile strength and 0.2% proof stress, but decreases in elongation, Charpy impact value, formability and corrosion resistance. Particularly, a coarse CaAl_2Si_2 compound increases with increasing Ca content, resulting in the drastic degradation of elongation and impact value. Therefore, amount of Ca remained in the 3003 alloy should be less than 0.1%. (3) In Al-Mg-Si (6061) alloy, tensile strength and 0.2% proof stress are markedly lowered because crystallized compounds increases with increases in V,Mn and Ca contents. The compounds largely contain silicon which contributes to age hardening in 6061 aluminum alloy. Elongation and impact value are degraded due to the existence of the coarse compound in the V-containing alloy ; unchanged in the Mn-containing alloy ; and upgraded due to softening of matrix phase and the fine-distributed compounds in the Ca-containing alloy. There is no effect of Zr content up to 0.3% on the various properties of 6061 aluminum alloy. It's required that V,Mn and Ca contents in 6061 aluminum alloy are less than 0.2%, 0.4% and 0.1% respectively to guarantee tensile properties satisfying JIS values. Less