Development of High Stiffness and High Thermal Stability Aluminum Alloy Prepared from Rapidly Solidified Rebbons by Composite Forming Process

In order to obtain alloy design conditions for high strenght aluminum alloy,especially with highAl-8wt%Fe and Al-8wt%Fe-1wt%Zr alloys prepared from rapidlysolidified ribbons and SiC whisker/aluminum composites processed by high pressure squeeze castingwere characterized microscopically，1.快速解决方案是超级解决方案的基础with dendritic-cell结构. Fine dispersoids of metastable phase l_6 Fe in the cell bounaricesbecome coare in annealing at temperatures high than 350 C,resulting in sortening in ribbons. Thezirconium does not alter the microstructure,but suppress the coasening of dispersoids，2. Exteusion make longirudinal direction of ribbons，以及thermal stability is asstained.2align parallel to extrusion direction，resulting in laminated structure. The growth of disprtsoids during hot compactiopn,de-sagging and热extrucsion is suppessed by zirconum addition. It has the pinning errect on subgrains anddispersoids and the precpitation harcdening effect by al_3 Zr spherical pahse.3. SiC whisker/aluminumcomposites processed by high pressure squeeze casting merhod have extremely sound interface betweenSiC whiskers and matric and have no void defects. In SiC whisker/Al-Cu-Mg of Al-Zn-Cu alloycomposites,the hardness value at -quenched state is very high，它是在aging的不确定阶段。

In order to obtain alloy design conditions for high strenght aluminum alloy,especially with high stiffness and high thermal stability. Al-8wt%Fe and Al-8wt%Fe-1wt%Zr alloys prepared from rapidly solidified ribbons and SiC whisker/aluminum composites processed by high pressure squeeze casting were characterized microscopically, calorimetrically and mechanically.1. Rapidly solidified ribons are consist of super solid solution with dendritic-cell structures. Fine dispersoids of metastable phase L_6Fe in the cell bounarices become coare in annealing at temperatures high than 350゜C,resulting in sortening in ribbons. The addition of zirconium does not alter the microstructure,but suppress the coasening of dispersoids, and then the thermal stability is asstained.2. Exteusion make longirudinal direction of ribbons align parallel to extrusion direction, resulting in laminated structure. The growth of disprtsoids during hot compactiopn,de-sagging and hot extrucsion is suppessed by zirconum addition. It has the pinning errect on subgrains and dispersoids and the precpitation harcdening effect by Al_3Zr spherical pahse.3. SiC whisker/aluminum composites processed by high pressure squeeze casting merhod have extremely sound interface between SiC whiskers and matric and have no void defects. In SiC whisker/Al-Cu-Mg of Al-Zn-Cu alloy composites, the hardness value at as-quenched state is very high and it is retained until stage of over aging.