Latest research advances on magnesium and magnesium alloys worldwide

Recent developments in high-strength Mg-RE-based alloys: Focusing on Mg-Gd and Mg-Y systems

A Review on Casting Magnesium Alloys: Modification of Commercial Alloys and Development of New Alloys

Magnesium, the lightest structural metal, is approximately four times lighter than steel—the most widely used metal in industrial applications. Currently available Mg alloys, however, are impractically expensive for use in automotive structural components, as severe ductility problems require forming operations at elevated temperatures and an exclusion from critical safety components. With a strong impetus in research having sprung up during the last two decades, addition of rare-earth elements in small quantities emerged as a potential solution for simultaneously delivering the ductility and weight requirements for automotive applications. These improvements are arguably achieved by virtue of texture weakening and enhancement of non-basal slip. However, ways by which rare-earth elements modify texture remain very elusive, and no consensus on the driving mechanisms has been reached in the literature as of yet. We take a look back at different paradigms held for the action of rare-earth additions, and examine key facts that may reconcile controversies. We attempt to identify critical gaps and suggest venues to overcome them. These gaps, once filled, may promote Mg alloys to become a stronghold for lightweighting, which will exceptionally benefit our environment and wellbeing.

A review on the effect of rare-earth elements on texture evolution during processing of magnesium alloys

Magnesium (Mg) alloys have received a significant interest in the past 20 years, owing to a nonlinearly increasing demand for lightweight structural materials. Magnesium extrusions alloys to date h...

Magnesium extrusion alloys: a review of developments and prospects

Microstructure and mechanical properties of Mg–Gd–Dy–Zn alloy with long period stacking ordered structure or stacking faults

As-cast Mg–5Li–3Al–2Zn– x RE ( x  = 0–2.5 wt.%) alloys were prepared under the ambient of pure argon, and the effects of Ce-rich rare earths (RE) and heat treatment on the microstructure and mechanical properties of Mg–Li–Al–Zn-based alloy were investigated. The results show that the main phase compositions of Mg–5Li–3Al–2Zn (LAZ532) alloy consist of α-Mg and AlLi. With the addition of RE, Al-RE precipitate forms, and increases gradually, whereas AlLi phase decreases. The room temperature tensile test reveals that the addition of RE could clearly improves the mechanical properties of alloys which are further improved after heat treatment. In more detail, excellent tensile strength and ductility are obtained in 1.5 wt.% RE containing alloy in as-cast state. After heat treatment, the 1.0 wt.% RE containing alloy attains superior tensile strength. The differences in tensile strength are related to the morphology, distribution of second phases and solid–solution strengthening in different alloy systems. In addition, the fracture pattern of the alloy is predominantly brittle cleavage and tends to be quasi-cleavage with RE addition.

Effects of Ce-rich RE additions and heat treatment on the microstructure and tensile properties of Mg-Li-Al-Zn-based alloy

The effects of Cu additions (0.5–2.0 wt.%) on the microstructure and hardness of Mg–5Li–3Al–2Zn alloy were studied. Optical microscope, scanning electronic microscope, X-ray diffraction and energy dispersive X-ray spectroscope were employed to study the microstructure of the alloys. Results show that, as the Cu addition increases, the AlCuMg phase exists in the alloy. This phase can partially restrain the formation and growth of AlLi phase. The Brinell macrohardness of the as-cast alloys increases with the increase of Cu content. The Vickers microhardness of the phases of as-cast alloy was measured to analyze the strengthening mechanisms.

Effects of Cu addition on the microstructure and hardness of Mg–5Li–3Al–2Zn alloy

The as-cast Mg–5Li–3Al– x Ca ( x  = 0, 0.5, 1, 1.5 wt.%) was prepared with vacuum induction melting furnace, then processed by hot extrusion. The microstructures and tensile properties were investigated. The results show that the grains of as-cast alloys were refined gradually with the increase of Ca content from 0.5 wt.% to 1 wt.%, while the Ca content increases to 1.5 wt.%, the grain size increases. The microstructures of investigated alloys were further refined after hot extrusion. Both as-cast and as-extruded Mg–5Li–3Al–0.5Ca alloys have the highest mechanical properties, which is mainly attributed to the grain refinement caused by the addition of Ca and the formation of strengthening phase, Al 4 Ca. When the addition of Ca is up to 1–1.5 wt.%, the tensile properties of alloys are worsened due to the excessive (Mg, Al) 2 Ca eutectic phase forming at grain boundary.

Effects of calcium on the microstructures and tensile properties of Mg–5Li–3Al alloys

An experimental investigation into the microstructure, mechanical properties and aging behaviors of as-extruded Mg–5Li–3Al–2Zn–1.5Cu alloy is conducted. The results show that, during the hot extrusion process, the large bulk intermetallic compounds (AlLi, AlCuMg and Al2Cu phases) of as-cast alloy are crushed into small bulk compounds. The dynamic recrystallization (DRX) takes place, which results in the refinement of grains significantly. A fibrous type texture of (0 0 0 2) basal plane is formed through the hot extrusion. Tensile tests reveal that the mechanical properties of the alloy are greatly improved after the hot extrusion. Due to the continuous and discontinuous precipitations of AlLi phases, the as-extruded alloy presents age hardening effect at the aging time of 14 h and 48 h, respectively.

Jiqing Li

Papers

Microstructure and mechanical properties of Mg–Gd–Dy–Zn alloy with long period stacking ordered structure or stacking faults

Effects of Ce-rich RE additions and heat treatment on the microstructure and tensile properties of Mg-Li-Al-Zn-based alloy

Effects of Cu addition on the microstructure and hardness of Mg–5Li–3Al–2Zn alloy

Effects of calcium on the microstructures and tensile properties of Mg–5Li–3Al alloys

Microstructure, mechanical properties and aging behaviors of as-extruded Mg–5Li–3Al–2Zn–1.5Cu alloy