TECHNOLOGY
熊本大学発マグネシウム合金
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TECHNOLOGY
Magnesium alloys, the lightest structural alloys,
have long been a promising material and have been used in various fields, such as transportation systems, electronic devices, and so on. Magnesium alloys could be tailored to be biocompatible and recyclable. Mg alloys could play a key role in the solutions for energy consumption and sustainable environmental due to their light weight and recyclability.
However, comparing with other light metals, Mg alloys have some compelling drawbacks for commercialization, such as insufficient strength, flammability, corrosion vulnerability, difficulty in forming and shaping at room temperature, and low thermal conductivity.
Professor Kawamura of Kumamoto University has been developing various new Mg alloys to solve these problems by exploring unique alloy and process design.
MG Port will develop various applications with the advanced alloys from Kumamoto University,
such as inflammable alloys, high thermal conductivity alloys, and biomedical alloys.
ALLOY
01
Inflammable Alloys
High-strength magnesium alloys inflammable at temperatures above 1000°C.
Background：Conventional commercial Mg alloys ignite at around 470-550°C and burn in solid state. This high flammability seriously limits Mg’s usage in aerospace structures. The high flammability also hikes the risks in storage and handling of materials, processing scraps, and molten metals.
Features：Professor Kawamura’s group has discovered a series of Mg-Al-Ca alloys that form a stable, uniform oxide film on the surface to retard burning. These alloys exhibit non-flammability at above 1000℃. In addition, the extruded alloys show a much higher mechanical strength than conventional Mg alloys and have a greater specific tensile strength than Al2024-T6.
・Typical alloy components：Mg-Al-Ca-Mn
・Nonflammable : Ignition temperature ≌ 1,050℃ （almost the boiling point of Mg)
Potential applications：Casting alloys・Alloys for machining processes・Materials for aerostructures・Heat treatment baths for steel components, etc.
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ALLOY
02
High strength with higher thermal conductivity (comparable to Al alloys) than conventional Mg alloys
High Thermal Conductivity Alloys
Background：The thermal conductivity of current commercial Mg alloys is merely 30-50% of that of Al alloys. This low thermal conductivity severely limits the use of Mg alloys for applications in thermal management devices in which heat dissipation is of a premium.
Features：The new Mg alloy system with much higher thermal conductivity than those of conventional Mg alloys and die-cast Al alloys (e.g., ADC12). In addition, the extruded material of this advanced Mg alloy system shows much higher mechanical strength than conventional Mg alloys (e.g., AZ31, AZ91) and has greater specific strength than Al2024-T6.
・Typical alloy components：Mg-Al-Ca-Mn
・Themal conductivity ： 120W/m・K (Commercial Mg alloys show ～50W/m・K)
Potential applications：Electronic devices・Heat-dissipating materials for LEDs・Manufacturing equipment (solder reflow pallets, etc.)・Cooking utensils, etc.
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ALLOY
03
Alloys for Medical Devices
Alloys with sufficient strength and corrosion resistance for biomedical applications
Background：Magnesium alloys have a high potential for use in biomedical devices. Magnesium is an essential element in our bodies and it is highly biocompatible. In addition, it dissolves in the body and gets flushed out after a designed functionality. Its low density also lessens our burden. But sufficient mechanical strength and high corrosion resistance are needed for applications in biomedical devices, such as bone fixtures and vasodilation stents.
Features：The novel biomedical Mg alloys with high strength and excellent corrosion resistance using a rapid solidification process:
For the cardiovascular system - Mg alloys with enough strength to maintain its shape and form of thin-gauge wires in blood vessels and streams, such as stents. It contains alloying elements of zinc and yttrium.
１.
For orthopedic applications - Mg alloys with sufficient strength for bone fixation. It could also provide benefits for bone regeneration. It contains zinc, calcium, and strontium as alloying elements.
２.
Potential applications：Cardiovascular medical devices: stents, flow diverters, etc.
Orthopedic medical devices: bone fixation devices, implants.