Anodization Replica of Precipitates in Age-Hardening Ti Alloys

摘要

Precipitation-hardening is one of the important strengthening mechanisms which governs the mechanical properties of various kinds of alloys. To characterize the precipitates in age-hardening Ti alloys, traditional metallography and transmission electron microscopy as well as metallurgical replica have been employed for either destructive or nondestructive testing. However, these characterization methods usually depend on skilled sample preparation and analysis,which lacks a good repeatability and sufficient imaging contrast. In the present work,our recent progress is reported in developing a novel replica method to characterize the precipitates in age-hardening Ti alloys. Based on a weak anodization and ultrasonic treatment, anodization replicas of various kinds of precipitates and grain boundaries are successfully fabricated in BT22 and TilOCr alloys. The phase-dependent anodization at different phase areas resulted in the formation of diversified replicas. The in-situ geometric replicas of the precipitates enable us to conduct a multi-scale and multi-dimensional characterization of both the primary and secondary precipitates, which shows great advantages over traditional characterization methods.