时效处理对TBe2微细游丝材料组织及性能的影响

Effect of aging treatment on microstructure and properties of TBe2 tiny hairspring material

制备了厚度为0.01 mm,宽厚比为22.5细晶超薄微细TBe2游丝材料,对其进行320℃真空时效处理,保温时间分别为1、2、4、8和16 h,通过透射电镜、X射线衍射仪对材料的组织和时效析出情况进行了分析,对材料的强度和电导率进行了测试,并用电子探针对拉伸试样的断口进行了分析。结果表明:厚度减薄对细晶TBe2的强度没有明显影响,但会使力学性能对时效时间较敏感。经典时效工艺320℃×2 h可明显提高TBe2游丝材料的强度及电导率,分别可达1585 MPa及32%IACS。冷轧态游丝材料的拉伸断口呈准解理断裂机制,经典时效处理后材料的断口呈韧窝断裂,且两者都为脆性断裂。

The fine grain and ultra-thin TBe2 fine filament hairspring material with thickness of 0.01 mm and width thickness ratio of 22.5 was prepared and then aged at 320℃for 1,2,4,8 and 16 h in vacuum furnace,respectively.The microstructure and aging precipitation of the material were studied by transmission electron microscopy(TEM)and X-ray diffractometer(XRD).The strength and conductivity of the material were tested,and the fracture morphology of the tensile samples was analyzed by electron probe microanalysis(EPMA).The results show that thickness thinning has no obvious effect on the strength of the fine-grained TBe2,but it will make the mechanical properties more sensitive to aging time.The strength and conductivity of the TBe2 hairspring material can be significantly improved after aging at 320℃for 2 h,which are 1585 MPa and 32%IACS,respectively.The fracture mechanism of the cold-rolled hairspring material is quasi-cleavage fracture,while that of the hairspring material treated by classical aging process is dimple fracture,and both of them are brittle fracture.