热处理温度对半固态挤压锡青铜组织性能的影响

Effect of heat treatment temperature on microstructure and mechanical properties of semi-solid extruded tin bronze

摘要:

本文以半固态挤压ZCuSn10P1锡青铜为研究对象,采用光学显微镜、扫描电镜、显微硬度仪、布氏硬度计、拉伸试验机研究了热处理温度对半固态挤压锡青铜微观组织和力学性能的影响规律。结果表明：热处理对半固态挤压锡青铜强度、硬度和组织影响较大。当热处理温度由250℃升高至650℃时,锡青铜抗拉强度先增加后降低,延伸率增加；布氏硬度先增加后降低；固相和固液界面显微硬度增加,液相显微硬度降低；固相平均晶粒尺寸增加,但热处理温度650℃时组织已不是球状而变成蔷薇状。随温度增加,固相中Sn和P元素增加,元素偏析减弱。综合性能较佳的热处理工艺为350℃保温120min,此时锡青铜抗拉强度为402 MPa,延伸率为4.5%,布氏硬度为136HBW,与未热处理前分别提高了3.88%、60.71%、6.25%。

Abstract:

The semi-solid extruded ZCuSn10P1 tin bronze was used as the research object. The effects of heat treatment temperature on microstructure and mechanical properties of semi-solid extruded tin bronze were investigated by using optical microscopy, scanning electron microscopy, microhardness test, Brinell hardness test, tensile test machine. The results indicate that the heat treatment has a great effect on the strength, hardness and microstructure of semi-solid extruded tin bronze. With the heat treatment temperature increase from 250℃ to 650℃, the tensile strength of tin bronze increases first and then decreases, the elongation increases, the Brinell hardness increases first and then decreases. The Vickers hardness of the solid zone and solid-liquid interface increases, however, the liquid zone decreases. The average grain size of solid phase increases, while it is not spherical but rose-like with the temperature increases up to 650°C. With the increase of temperature, the element contents of Sn and P in the solid phase increase, and element segregation weakens. The comprehensive mechanical properties of tin bronze at heat treatment temperature 350°C for 120 min are fine. At this time, the tensile strength is 402 MPa, elongation is 4.5%, Brinell hardness is 136 HBW, compared with before heat treatment, it increases by3.88%, 60.71%, and 6.25%, respectively.