Scandium Alloy

A:

• Scandium (Chemical symbol Sc and atomic number 21) is a silver-white light transitional metal. It is classified as a rare-earth element.
• Its main properties are its light weight, high melting point and small ionic radius. Scandium is only the 50th most common element on Earth, but it is the 23rd most common element in the Sun.
• Due to the small size of its ions, it does not selectively combine with common ore-forming anions and rarely forms concentrations higher than 100 ppm in nature.
• Scandium is mainly used, at grades of 0.1 to 0.5%, in aluminum alloys for aerospace and sports applications, including bicycle frames, tennis rackets and baseball bats.
• The main reason to add scandium is that it adds strengths like no other element to lightweight aluminium alloys. More precisely, due to its fine grain refinement, scandium alloys reduce hot cracking in welds, increase strength in the welds and deliver better fatigue behaviour.
• It is also used in halogen lamps in the scandium iodide form in order to obtain a light close to that of natural sunlight.
• Scandium has two very important potential end-uses, notably in Europe: Solid Oxide Fuel Cells for energy storage and Sc-Al alloys in aerospace and automotive sectors.

A:

• The global producers of scandium are China 66%, Russia 23%, Ukraine 7% and Kazakhstan 1%.
• The global supply of scandium originates from primary sources such as ore feedstock, and secondary sources from mining production such as concentrates, metallurgical slags and residues.
• Scandium is typically produced as a co-product or by-product during processing of various ores (e.g., iron ore, REEs, titanium, zirconium, uranium, thorium, aluminium, tungsten, tin, tantalum, apatite, nickel and cobalt) and/or recovered from previously processed tailings and residues (USGS 2021 & 2022).

A:

• Scandium is not traded on any metals exchange as scandium products are sold between private parties at undisclosed prices.
• Data on scandium (Sc) production is very patchy and incomplete. According to the USGS (2022) the annual Sc production is estimated to 10-20 t; DERA (2021) assumes the figure to be around 14-16 t. Sc demand and supply are highly concentrated. With about 75% (>10 t) of the global annual production China is the largest producer of Sc. Other producers Russia (1-2 t/y) and the Philippines (ca. 1 t/y) (DERA, 2021).

A: Scandium, like other metals alloyed with aluminum, imparts strength and desirable properties to aluminum, and does so in some measure to each of the eight alloy families (Series). Scandium additions generate strength by promoting a smaller, even-sized grain structure in alloys during solidification. Scandium shows better strength response in some alloy families than others, but almost always with quite small additions – between 0.1% and 0.45% Sc.

A: Scandium delivers transformative strength without the need for problematic and costly heat treatments. Specifically, scandium additions can increase yield strength on a 5000 Series to between 300Mpa and 450Mpa, depending on the amount of addition, while maintaining elongation (ductility) figures of 12-15.

A: Health effects of scandium:

Scandium has no biological role. Only trace amounts reach the food chain, so the average person's daily intake is less than 0.1 microgram.

Scadium is not toxic, although there have been suggestions that some of its compounds might be cancerogenic.

Scandium is mostly dangerous in the working environment, due to the fact that damps and gasses can be inhaled with air. This can cause lung embolisms, especially during long-term exposure. Scandium can be a threat to the liver when it accumulates in the human body.

A: Effects of scandium on the environment:

Scandium is dumped in the environment in many different places, mainly by petrol-producing industries. It can also enter the environment when household equipment is thrown away. Scandium will gradually accumulate in soils and water soils and this will eventually lead to increasing concentrations in humans, animals and soil particles.

With water animals scandium causes damage to cell membranes, which has several negative influences on reproduction and on the functions of the nervous system.

A: Scandium aluminum alloys are a winning combination of scandium and aluminum metal. The addition of scandium to aluminum limits the excessive grain growth that occurs in the heat-affected zone of welded aluminum components.

A: Aluminum Magnesium Scandium features good weldability, excellent damage tolerance, good corrosion resistance, creep-formability. Aleris AlMgSc alloy AA5024 H116 allows simplification of the manufacturing process of aircraft fuselage components. With AA5024 H116 AlMgSc, stringer reinforced aircraft fuselage components can be either Laser Beam Welded (LBW) or Friction Stir Welded (FSW) when the individual parts are still flat, without any prior treatment. The single or double curvature of the fuselage part required for the aircraft body is achieved by creep forming at elevated temperature.

Recommended for use as fuselage skin sheet with medium strength but excellent damage tolerance and corrosion properties and can potentially replace traditionally used 2xxx alloys even as drop-in solution.

A: Some disadvantages of aluminum-lithium alloys include:

• Reduced ductility
• Reduced fracture toughness
• Anisotropy of in-plane properties
• Need for cold work to attain peak properties
• Accelerated fatigue crack extension rates

A: Al–Li alloys are lighter and have high tensile and yield strength compared to the conventional high-strength aluminium alloys. They are resistant to fatigue crack propagation; however, their corrosion resistance still needs to be improved.