THE PRECIPITATION BEHAVIOR OF α PHASE IN A NEW NEAR β TITANIUM ALLOY Ti-7333 DURING AGING PROCESS

摘要

In near p titanium alloys, the precipitation morphology, size and spatial arrangement are strongly correlated to the precipitation behavior occurring during aging treatment. In this work, a newly near p titanium alloy Ti-7333 was subjected to solution and ageing treatment. And the evolution of a phase was analyzed by microstructure observation and quantitative statistics. The results indicated that The needle-like secondary a precipitate morphology formed after solution treatment above β phase followed with aging treatment. When the aging temperature reduced, the length and width of a phase reduced while the volume fraction increased, otherwise the amount and size of a precipitation increased with the increased of the aging time. The increasing in the volume fraction of a phase resulted in the strengthening of the micro-hardness of the alloy. The slower aging respond of a precipitate was observed in Ti-7333 alloy, which resulted from the more slow-diffusing element Mo in Ti-7333 alloy. The more slow-diffusing element Mo in Ti-7333 alloy also resulted in the precipitation of linear liked dot a phase after short time aging.