(1. 中南大學(xué) 材料科學(xué)與工程學(xué)院，長(zhǎng)沙 410083；
2. 中鋁洛陽(yáng)銅業(yè)有限公司，洛陽(yáng) 471039)
摘 要: 采用雙輥鑄軋技術(shù)制備AZ31鎂合金板坯，利用X射線衍射、金相顯微鏡、掃描電子顯微鏡以及能譜分析等技術(shù)對(duì)該板坯的物相進(jìn)行分析。結(jié)果表明： 雙輥鑄軋AZ31鎂合金板坯中的物相主要有α-Mg枝晶、枝晶間富溶質(zhì)α-Mg和不規(guī)則的塊狀Mg17(Al, Zn)12相組成的離異共晶以及彌散分布于晶內(nèi)的星形細(xì)小Al8Mn5相；在雙輥鑄軋過(guò)程中，隨著Mg液溫度的降低，過(guò)飽和的Mn以Al8Mn5相的形式從Mg液中析出，而后細(xì)小的Al8Mn5相隨著α-Mg初晶的長(zhǎng)大進(jìn)入枝晶胞內(nèi)部；α-Mg初晶長(zhǎng)大的同時(shí)，Al、Zn等元素在枝晶間未凝固的液相中富集，最終在枝晶間形成依附于初晶的富溶質(zhì)α-Mg和不規(guī)則的塊狀Mg17(Al, Zn)12相組成的離異共晶。
關(guān)鍵字: AZ31鎂合金；雙輥鑄軋；物相
plate blank
（1. School of Materials Science and Engineering, Central South University, Changsha 410083, China;
2. CHINALCO Luoyang Copper Co. Ltd., Luoyang 471039, China）
Abstract: AZ31 Mg alloy plate was fabricated successfully by twin-roll casting technology, and the phases in the plate were analyzed by X-ray diffraction, metallographic microscope, scanning electron micrograph and an energy dispersion X-ray spectroscopy. The results show that the phases of twin-roll casting AZ31 Mg alloy are composed of α-Mg dendritic, divorced eutectic with α-Mg and irregular massive Mg17(Al, Zn)12, and fine star-shaped Al8Mn5. During the twin-roll casting process, the supersaturated Mn precipitates from the melt in the form of Al8Mn5 phases, and then the little Al8Mn5 phases enter into the dendritic with the α-Mg primary crystals growing up with temperature decreasing. At the same time, Al and Zn enrich in the remaining melt between dendritics, which leading to the formation of the divorced eutectic composed of enriched α-Mg leeching on the primary crystal and irregular massive Mg17(Al, Zn)12 phases in the interdendritic.
Key words: AZ31 Mg alloy; twin-roll casting; phase
