锆微合金化增强铝合金的研究进展

Research progress in Zr-microalloying strengthened aluminum alloys

锆(Zr)元素是铝合金中研究较为深入、实际应用较为广泛的微合金元素之一。由于Zr在铝中具有低的固态扩散速率且可形成低密度、高熔点、低界面错配度的Al_(3)Zr弥散相,因此合金展现出高温下服役的潜力。然而,Al_(3)Zr粒子的弥散强化效果主要受到粒子低数量密度或体积分数的制约;此外,多元合金体系凝固、变形、热处理过程中多组元间交互作用复杂,Al_(3)Zr弥散强化与各体系中本征相强化作用往往难以兼得,上述问题均对合金的力学强度造成了不利的影响。本文综合近年来的相关报道,对含Zr铝合金中Zr的存在形式、析出和粗化行为以及强化机制进行了概述;简要介绍了复合微合金化促进Al_(3)Zr析出机理与最新研究结果;对某些体系铝合金中Zr微合金化的应用进行了归纳与总结,结合当前新型耐热铝基合金发展的新趋势,指出铝合金内Zr的微量添加对调控微结构、提升室温和高温强度的重要意义。

Zr is one of the most deeply investigated and widely used microalloying elements.The low diffusivity of Zr and the formation of thermal-stable Al_(3)Zr dispersoids with the properties of low density,high melting temperature and low interface misfit in Al matrix,making Zr owing a broad prospect of application in developing heat-resistant Al alloys.However,strengthening by Al_(3)Zr has been limited by either low number density or low volume fraction.In addition,the interaction among multiple components is very complex in multi-component Al alloys during solidification,deformation and heat treatment,and it is very difficult to achieve a good combination in strengthening of Al_(3)Zr with the intrinsic phase of each system.In this review,the existing form,the precipitation and coarsening behavior,and the strengthening mechanism of Zr element in Zr-containing Al alloys were summarized.The mechanism of complex microalloying with multiple elements on promoting Al_(3)Zr dispersion was briefly introduced.Finally,the effects of Zr addition on several series of Al-based alloys were summarized.In sum,microalloying with Zr is of great significance for regulating microstructure and improving room temperature/high temperature strength in Al alloys.