一种快速凝固铝锂合金的低温光滑和缺口拉伸性能

 研究了快速凝固Ａｌ-４．７４Ｃｕ-１．３０Ｌｉ-０．３８Ｍｇ-０．４２Ａｇ-０．２１Ｚｒ合金在室温到液氦温度（７７Ｋ）范围内的光滑和缺口拉伸性能,并用扫描电镜观察了断口形貌,用透射电镜分析了合金组织及变形后的位错组态。结果发现,随着温度降低,合金强度线性升高,形变硬化能力增强,而延伸率的变化则取决于不同的时效态。尽管合金缺口强度随温度降低而减小,但７７Ｋ下该合金在欠时效态其缺口性能仍明显优于传统铝合金。

LOW TEMPERATURE TENSILE AND NOTCHED TENSILE PROPERTIES OF A RAPIDLY SOLIDIFIED Al-Li ALLOY

The low-temperature tensile and notched tensile properties of rapidly solidified Al-4.74Cu-1.30Li-0.38Mg-0.42Ag-0.21Zr alloy have been studied with tests camed out from room temperature down to 77K. The fractography is examined by means of scanning electron microscopy(SEM) while transmission electron microscopy is employed to study the microstructure and dislocation mopohologies.It is discovered that the allov shows a linear in-crease in strength and a gain in deformation hardening capability when temperature is lowered while the change ofelongation-to-fracture differs with different aging states. The alloy displays much better notch perfonnance than conventional aluminum alloys at 77K regardless of the de-crease in notch-strength with drop in temperature.The change of dislocation morphologies is found to play an important role in the improvement of strength and ductility at low temperatures.