A researcher team from the Institute of Metal Research, Chinese Academy of Sciences (IMR, CAS) led by Prof. ZHANG Jian has published a comprehensive review on recrystallization in single crystal superalloys, providing systematic evaluation methods and control strategies for this critical defect in aerospace engine components. 

The work, designated as an "Editor's Choice" article, published in Metallurgical and Materials Transactions A.

Single crystal superalloys serve as core materials for hot-section components in aircraft engines and gas turbines, where strict control over metallurgical defects is crucial. Recrystallization,a common defect in single crystal blades, can significantly compromise engine safety and reliability.

Unlike other casting defects that forming during directional solidification, recrystallization primarily occurs during subsequent heat treatment processes, though it is influentced by  manufacturing techniques, blade geometry, and auxiliary materials. Its multi-disciplinary, multi-physical field, and multi-scale nature of recrystallization has made prediction, detection, and control a longstanding international research challenge.

Prof. ZHANG Jian's team, provides an in-depth analysis of plastic deformation in as-cast single crystal superalloys and explores the mechanisms of recrystallization nucleation and growth. The review systematically evaluates the effects of plastic strain, heat treatment, crystal orientation, composition, and particularly geometric parameters of castings on recrystallization behavior, proposing assessment methods for recrystallization tendency.

The article also details the impact of recrystallization on high-temperature properties, including tensile strength, creep, and fatigue resistance of various single crystal superalloys, and discusses the underlying damage mechanisms. Furthermore, it summarizes recent advances in non-destructive testing techniques for recrystallization defects, including ultrasonic testing and high-energy X-ray methods, while proposing prevention strategies through process optimization, surface treatment, and recovery heat treatment.

This work provides a valuable guidance for both academic research and industrial applications in the field of high-temperature materials, contributing to improved manufacturing quality and service reliability of single crystal superalloy components.