半固态固溶及时效对Mn-Cu合金组织和性能的影响

Effect of semi-solid solution and aging on microstructure and properties of Mn-Cu alloy

摘要:

采用真空感应熔炼法制备Mn65-Cu23.75-Zn3-Al3-Ni3-Fe2-Ce0.05 (at%)合金。对该合金进行轧制处理,然后进行均匀化退火。分别在850 ℃和950~1050 ℃对合金进行普通固溶及半固态固溶处理,随后在430 ℃时效0~16 h。研究半固态固溶温度及时效时间对Mn-Cu合金组织、阻尼性能和力学性能的影响。结果表明：普通固溶合金组织由单一γ-MnCu相构成,而半固态固溶合金组织则由富Mn和贫Mn的γ-MnCu相构成,且随着半固态固溶温度的升高,贫Mn相的含量不断增加。合金阻尼性能随时效时间的延长呈现出先上升后下降趋势。在最优时效条件下,较低的半固态固溶温度可提高合金的阻尼性能,而较高的半固态固溶温度则会降低其阻尼性能。和S850合金相比,S950合金的强塑积提高了约70%。但随着半固态固溶温度的增加,合金强塑积又有所下降。

Abstract:

Mn65-Cu23.75-Zn3-Al3-Ni3-Fe2-Ce0.05 (at%) alloy was prepared by vacuum induction melting method, and then rolled at 400 ℃ with a height reduction of 40% and further annealed at 800 .℃ for 5 h. The alloy samples were solid solution and semi-solid solution treated at 850 ℃ and 950~1050 ℃ for 20 min respectively, and then aged at 430 ℃ for 0~16 h. The effects of semi-solid solution temperature and aging time on the microstructure, damping capacity and mechanical properties of Mn-Cu alloys were studied. The results show that the microstructure of solid solution treated alloy is composed of a single γ-MnCu phase, while that of the semi-solid solution treated one comprises Mn-rich and Mn-poor γ-MnCu phases. The amount of Mn-poor γ-MnCu phase gradually rises with increase in semi-solid solution temperature. The damping capacity of the alloy firstly increases and then deceases with increasing the aging time. Under optimal aging conditions,,the damping capacity of the alloy is improved at a relatively lower semi-solid solution temperature while degraded at a relatively higher semi-solid solution one. The tensile properties of the alloys semi-solid solution treated at 950 and 1000 ℃ are improved compared to the alloy solid solution treated at 850 ℃ (especially, the product of strength and ductility of S950 alloy is 70% higher than that of S850 one). However, the product of strength and ductility of the alloy decreases instead with further increase in semi-solid solution temperature.