温度和形变对Mullite/Al-4.5Cu复合材料及其基体合金时效行为的影响

Effect of Temperature and Deformation on the Ageing Behaviour of Mullite/Al-4.5Cu Composite and Its Base Alloy

用挤压铸造方法制备Mullite/Al 4 .5Cu复合材料及其基体合金。用硬度测试 (HB)、差示扫描量热仪 (DSC)和透射电镜 (TEM )等手段 ,研究了温度和形变对复合材料及其基体合金时效行为的影响。结果表明 :无论是复合材料还是基体合金 ,随时效温度的升高 ,峰值硬度降低 ,时效析出过程加快 ;莫来石纤维除了能明显提高Al 4 .5Cu合金的时效硬度外 ,还能加速其时效析出过程 ;固溶淬火后立即形变 ,能十分明显地加速复合材料及其基体合金的时效析出过程 ;纤维和形变都能明显抑制GP区的形成 ,但二者对θ相析出反应的影响存在差异。

Short mullite fiber reinforced Al 4.5Cu composite and its base alloy were produced by squeeze casting. The effect of temperature and deformation on the ageing behaviour of the composite and its alloy has been studied by means of hardness measurement (HB), differential scanning calorimetry (DSC) and transmission electron microscope (TEM). It is shown that the aged hardness is largely increased and the ageing process is obviously accelerated with increasing the ageing temperature both in the composite and in the base alloy. Short mullite fiber not only increases the aged hardness of Al 4.5Cu alloy, but also accelerates the age precipitation process. Deformation after quenching in ice water can considerably speed up the age precipitation progress of the two testing materials, and the GP zone formation is heavily suppressed by both short mullite fiber and deformation. But there is a difference of effectiveness between the fiber and the deformation on θ precipitation in Al 4.5Cu alloys.