发动机零部件制造用的铝合金不仅要求在20～200℃具有高的抗拉强度,还要有较高的抗疲劳性能。但是常用的7075合金虽具有高的室温强度,但当温度≥200℃时,强度就急剧下降,而2618合金虽然有相当高的高温强度,但在室温下其抗拉强度与疲劳强度则 The aluminum alloy used in the manufacture of engine parts not only requires high tensile strength at 20-200 ° C but also high fatigue resistance. However, although the commonly used 7075 alloy has high room temperature strength, its strength decreases sharply when the temperature is higher than or equal to 200 ° C. However, although the 2618 alloy has a relatively high high temperature strength, its tensile strength and fatigue strength at room temperature