【摘要】 研究了Al-Fe基合金挤压铸造过程中,挤压力对铸件组织和力学性能的影响。研究发现,挤压力可以使针片状Al3Fe相尖锐的棱角钝化,由针片状向短棒状、椭球状转变,还可以看到较长的Al3Fe相发生断裂。合金的力学性能明显上升,比压为936 MPa时,合金的硬度为HB91.25,相比于铸态上升了23.7%。同一铸件从外部到内部,Al3Fe相尖锐的棱角发生钝化,同时内部晶粒由于散热作用较差,组织长的比较粗大,临近外壳层的部位组织在较大过冷度的作用下最为细化。经T6热处理后,挤压铸造合金的性能因富Cu相向Al3Fe相周围富集而大幅度下降,所以该合金不适合传统的T6热处理。更多还原

【Abstract】 The influences of the extrusion pressure on the microstructure and properties in squeeze casting process of Al-5.5Fe base alloy were studied. After squeeze casting, the microstructures of alloy were fined obviously. When the extrusion pressure increases, the sharp edges of Al3 Fe phase decreases as well as more rounded, the needle flake transform into elasticity shape, meanwhile, we also can see a long Al3 Fe phase split.The mechanical properties of the alloy increased dramatically, when the extrusion pressure rises to 936 MPa, the hardness of alloy is HB 91.25 and is 23.7% higher than the as-cast one. The same casting from external to internal, the sharp edge of Al3 Fe phase changed more rounded. And, the microstructure grew coarsening because of the poor cooling effect, however, the parts near the shell layer refined most due to a greater degree of under cooling. After T6 heat treatment, the properties of squeeze casting alloy declined substantially due to Cu-rich phase gather round Al3 Fe phase, therefore, this alloy is not suitable for conventional T6 heat treatment.更多还原