钛化物在铝熔体中的沉淀现象

Deposition of compounds containing Ti in Al melts

为了研究导致细化衰退的钛化物沉淀现象,以中间合金为细化剂对工业纯铝进行了细化处理,得到了不同沉淀时间的沉淀试样,利用金相、SEM等技术分析了试样底部沉淀物的显微组织.结果表明:加入中间合金后,试样均存在明显的钛化物沉淀现象,且沉淀物中既有TiC(TiB2)化合物,也有TiAl3化合物;沉淀物中的TiAl3与原中间合金中的TiAl3形态一致,说明原中间合金中的一些TiAl3化合物在没有分解完全时就已沉到试样底部;AlTiC中间合金比AlTiB中间合金的钛化物沉淀倾向明显.

In order to study deposition of compounds containing Ti, which causes recession of refinement, Al-5Ti-1B and Al-3Ti-015C master alloys were added into pure Al, and the microstructures of deposits at the sample bottoms were investigated through metallographic examination and SEM. The experimental results show that there is obvious deposit at the sample bottom in less than 15 min after addition of AlTiC or AlTiB master alloys; the deposit contains TiC(TiB2) and TiAl3; the morphologies of TiAl3 in deposit are consistent with those in original master alloys, which proves that TiAl3 in the master alloys deposit to the sample bottom before it decomposes completely;and compounds containing Ti of AlTiC master alloy is more likely to deposit than that of AlTiB master alloy.