A Novel Insight Toward Zr Poisoning on Grain Refinement of Al–5Ti–1B and Its Solution

Lili ZHANG*, Linjie YANG, Jiuzhou ZHAO*, Zheling SHEN, Qian LI, Hongxiang JIANG, Jie HE*

*Corresponding author for this work

Research output: Journal Publications and ReviewsRGC 21 - Publication in refereed journalpeer-review

2 Citations (Scopus)

Abstract

Adding Al–5Ti–1B to the melt is a universal practice to refine the microstructure of aluminum alloys. However, its major problem is susceptibility to the appearance of element Zr. A novel insight toward Zr poisoning effect on grain refinement of Al–5Ti–1B as well as its solving method is proposed in this work. For an Al–Zr melt with the existence of solute Ti and TiB2, solutes Zr and Ti show almost the same effect on the kinetic behaviors of TiB2 or (Ti, Zr)B2. Solute Zr leads to the formation of Zr-contained multi-layers (ZCMLs) on the TiB2 surface in the form of (Ti, Zr)B2. Different from solute Ti, solute Zr shows no segregation tendency to the Al(L)/TiB2 interface and decreases the interfacial atomic ordering level. Zr poisoning effect is determined by the Zr mole fraction ΧInZr in the interfacial monolayer between ZCMLs and Al melt. For a given Zr concentration, ΧInZr and Zr poisoning effect decreases with Ti concentration of the melt. Zr poisoning effect can be vanished using hundreds of ppm of solute Ti within its allowed limit in most Al alloys while keeping the addition level of Al–5Ti–B unchanged. © The Minerals, Metals & Materials Society and ASM International 2024.
Original languageEnglish
Pages (from-to)2765-2775
JournalMetallurgical and Materials Transactions B: Process Metallurgy and Materials Processing Science
Volume55
Issue number4
Online published3 Jun 2024
DOIs
Publication statusPublished - Aug 2024

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