耐热铝基合金研究进展:微观组织设计与析出策略

Recent Progress in High-Temperature Resistant Aluminum-Based Alloys:Microstructural Design and Precipitation Strategy

工业选材在满足强度要求以保证结构安全之余,通常也需要尽可能兼顾轻量化以使机械结构更加轻盈。当仅仅考虑室温服役性能时,大量的商用铝合金材料因其优异的室温力学性能可供备选,并通常能很好地契合"轻质-高强"这一目标。然而,对于需要在300~500℃中温区间服役的构件,铝合金的上述优势则荡然无存。其主要原因在于传统高强铝合金赖以强化的析出相在200℃以上便将发生快速失稳粗化,导致材料丧失强化效果并快速软化失效。而若以更耐热的钛合金、高温合金等作为替代,则随之带来的结构增重与成本提高又令设计者甚觉"重材轻用"。目前,在>300℃温度区间难以实现安全服役仍是轻质铝基材料开发的难点所在,而其关键的解决方案在于如何寻求微观组织的高温稳定化。本文从耐热铝合金中特异性的微观组织特点出发,综述近期业界在耐热铝基合金开发过程中关于强化相选择、合金化策略以及微观组织热稳定化的进展与内在构建机理,以期能够提供一些耐热轻质合金材料微观组织设计过程的普适性基本理论依据。

Many load-bearing industrial settings require light-weight structural materials with adequate strength.Although commercial aluminum(Al)alloys are suitable for room-temperature applications,their strength at elevated temperatures(300-500 oC)is largely reduced by coarsening of the strengthening precipitates.However,high-temperature alternatives such as titanium alloys are much heavier andmore expensive than Al alloys.Creating microstructures that remain stable over 300 oC is an important goal of the aluminum-manufacturing community.This article focuses on the recent development of hightemperature resistant Al-based alloys.Especially,it discusses the unique microstructural features,selection criteria of the strengthening phase,alloying effects,and microstructural stabilization of aluminum.The strategies summarized in this review are expected to realize the new microstructural architectures of light-weight alloys,which are currently limited to low-temperature service.