Abstract

The microstructure, mechanical property and corrosion behavior of gravity casting and centrifugal casting Mg–9Li–3Al–1Ca alloy were investigated. The results indicate that the Mg–9Li–3Al–1Ca alloy is mainly composed of α-Mg phases, β-Li phases and Al₂Ca phases. After centrifugal casting, the blocky and elongated α-Mg phases of the gravity casting alloy can be refined and spheroidized. Meanwhile, the amount of α-Mg and AlLi phases increases, however, the number of Al₂Ca phases decreases. Besides, a strong texture of β-Li phase on the (200) plane can be formed. The microstructure refinement and the decrease of Al₂Ca phases lead to the improvement of comprehensive property. The property of centrifugal alloys has gradient along radius direction because the strength of centrifugal force varies with the centrifugal radius. The centrifugal casting Mg–9Li–3Al–1Ca alloy at outside exhibits excellent comprehensive properties. The ultimate tensile strength and elongation of centrifugal casting alloy achieve the value of 198.3 MPa and 6.0%, corresponding to 83.6% and 300.0% increments compared with gravity casting ones, respectively. The corrosion current also decreases to 89.4 μA/cm², which attributes to the weakening of galvanic corrosion attributing to the decrease of number of Al₂Ca phases and the transformation of corrosion pattern caused by grain refinement.

Graphic Abstract

中文翻译：

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离心铸造改善Mg-9Li-3Al-1Ca合金的组织，力学性能和耐蚀性

摘要

研究了重力铸造和离心铸造Mg-9Li-3Al-1Ca合金的组织，力学性能和腐蚀行为。结果表明，Mg-9Li-3Al-1Ca合金主要由α-Mg相，β-Li相和Al ₂ Ca相组成。离心铸造后，重力铸造合金的块状和拉长的α-Mg相可以细化和球化。同时，α-Mg和AlLi相的数量增加，但是，Al ₂ Ca相的数量减少。此外，可以在（200）面上形成强的β-Li相织构。Al ₂的组织细化与还原Ca相导致综合性能的提高。离心合金的性质沿半径方向具有梯度，因为离心力的强度随离心半径而变化。外部的Mg-9Li-3Al-1Ca离心铸造合金具有出色的综合性能。离心铸造合金的极限抗拉强度和伸长率分别达到198.3 MPa和6.0％，与重力铸造相比分别增加了83.6％和300.0％。腐蚀电流也降至89.4μA/ cm ²，这归因于电腐蚀的减弱，这归因于Al ₂ Ca相数量的减少和晶粒细化引起的腐蚀方式的转变。

图形摘要