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用低成本的Al_2O_3-SiO_2系纤维作为增强相,通过加压铸造法制作ZL108合金复合材料,并对该复合材料和ZL108合金进行不同温度下的时效处理和压缩试验。通过DSC、EPMA和TEM分析认为:经488K、0.5h时效处理(T6处理)的V_f 20%的复合材料在573K以下的压缩屈服强度低于ZL108合金,是由于基体中的Mg与Al_2O_3-SiO_2纤维在加压铸造过程中起化学反应而生成MgAl_2O_4,损耗了基体中的大量Mg,导致基体铝合金时效硬化效果很差,所以压缩屈服强度低下。623K、720h保温后的V_f 20%的复合材料的压缩屈服强度比ZL108合金要高得多,是由于在这种温度环境下对ZL108合金来说是过时效,所以纤维的增强怍用显得明显。在高温(673K)下V_f 20%的复合材料的屈服强度比ZL108台金高一倍左右。不论在什么温度场合下V_f5%的复合材料的屈服强度比V_f 20%的复合材料都低。
Low-cost Al 2 O 3 -SiO 2 -based fibers were used as reinforcing phase to fabricate ZL108 alloy by pressure casting method. The composites and ZL108 alloy were aged at different temperatures and subjected to compression test. The results of DSC, EPMA and TEM showed that the compressive yield strength of composites with V_f 20% aged at 488K and 0.5h (T6 treatment) under 573K is lower than that of ZL108, which is due to the fact that Mg and Al_2O_3-SiO_2 fibers In the process of pressure casting chemical reaction to generate MgAl_2O_4, loss of a large amount of Mg in the matrix, resulting in matrix Al alloy aging hardening effect is poor, so the compression yield strength is low. The compressive yield strength of V_f 20% composites after 623K, 720h thermal insulation is much higher than that of ZL108 alloy due to the over-aging of ZL108 alloy in this temperature environment. At high temperature (673K) V_f 20% of the composite yield strength than ZL108 Taijin doubled. V_f5% composites have lower yield strength than V_f 20% composites at any temperature.