不同熔体热处理工艺后Al-Cu-Ti合金的晶粒细化及力学性能改善

Grain refinement and mechanical properties of Al-Cu-Ti alloys after different melt heat treatment processes

摘要:

本文研究了添加细化剂和不同热处理工艺（过热处理和热速处理）对Al-Cu合金的改性。分析了Al-Cu-Ti合金的相组成、凝固微观组织和力学性能。此外，采用差示扫描量热法（DSC）研究了Al-Cu-Ti合金在不同熔体热处理工艺后的熔体结构转变行为。实验结果表明，热速处理极大地细化了Al-Cu-Ti合金晶粒，且力学性能得到有效改善。通过对热力学相变分析，发现Al-Cu-Ti合金经过热处理和热速处理后的熔化潜热随着界面能的增大而变小，从而在一定程度上细化了合金的微观组织。

关键词:熔体热处理工艺;熔体结构;凝固组织;晶粒细化;力学性能

Abstract:

In this study, the modification of Al-Cu alloy by adding grain refiner combined with different heat treatments (superheat treatment and thermal rate treatment) is investigated. The phase composition, solidification microstructure and mechanical properties of Al-Cu-Ti alloys are analyzed. Moreover, the melt structure transformation of Al-Cu-Ti alloys after different melt heat treatments was studied by DSC. The experimental results showed that the thermal rate treatment greatly refined the grain of Al-Cu-Ti alloy and improved the mechanical properties. Through the analysis of thermodynamic phase transition, it was found that the latent heat of fusion of Al-Cu-Ti alloy after superheat treatment and thermal rate treatment became smaller due to the increase of interfacial energy, which leads to refine the microstructure of alloy to some extent.

Key words:Melt heat treatment process; Melt structure; Solidification structure; Grain Refinement; Mechanical properties