Aluminum-Composites show high stiffness, strength and wear resistance. The elastic modulus could reach values up to 220 GPa Conventional Aluminum alloys have an elastic modulus of 70-80 GPa. The elastic modulus could be changed by alloying elements, ceramic particles and fibers.
These alloys are made mostly via spray forming. The Silicon content could be up to 70%. Very high content Silicon alloys are used for semi- conductor devices. A very low CTE is important for this application.
For technical application Silicon contents up to 36% are in use for Pistons, Cylinder Liners and other high temperature components. These technical Aluminum-Silicon-Alloys show an elastic modulus of 85-100 GPa and good wear resistance. The machining behavior is good compared to conventional cast Aluminum-Silicon-Alloys.
Particles like Al2O3, SiC, TiB, TiC sowie AlN are used for the Aluminum-MMC-Alloys. Different processes like spray forming, gas-atomization, mechanically alloying, In-Situ reaction, wrought metallurgy and liquid infiltration are in use.
All particle reinforced Aluminum-Composites show a higher elastic modulus, a lower CTE and higher wear resistance compared to conventional alloys. The machining behavior is more difficult compared to standard alloys but depends strongly on particle-size and -system. The elastic modulus varies from 90 to 220 GPa.
Within the data sheets you will find more detailed information about the specific alloy.
Processing via liquid metal pressure infiltration
This is a very important process for technically used Aluminum-MMC-Alloys with high particle content. The ceramic particles and a binder are cold-iso-statically pressed and subsequently sintered. The binder is now out-gassed and the particles are connected in a 3D open-porous shape. Because of its open porosity the metal can flow, with a pressure, into the preform. The advantage of this sintered preform is that it shows some strength and can be easily handled. With some geometrical limitations near-net-shape components are feasible. The particle content could range from 30-70%. Many particle systems are in use.
The squeeze cast process is used fort he infiltration of the preform. This process is very comparable with pressure die casting. See also Information of DSC-Materials in the menu item, high temperature Aluminum alloys.
Aluminum Al-7SiC15 is a high strength Aluminum-Composite. The matrix alloys is the well known A7075 with 15% SiC particles. It is processed via spray forming. This alloy shows high strength, modulus and an acceptable ductility. The elastic modulus is around 100 GPa. It is important to note that also very large components could be supplied up to 3 meters in diameter.
A356-SiC15 is an Aluminum-Silicon-Alloy-Composite for elevated temperatures. This alloy contains 15% SiC particles. A356-SiC15 shows higher strength compared to A356 (AlSi7Mg) alloys. The modulus is around 102 GPa. It is important to note that also very large components could be supplied up to 3 meters in diameter.
Aluminum Al-TiB55 is a high strength, very high modulus Aluminum-Composite-Alloy. The matrix alloys is A2024. The alloy is processed via liquid metal infiltration of a ceramic perform. The particle system is TiB. The particle content is 55%. Al-TiB55 shows a very high strength of 640 Mpa and an exceptional high modulus of 203 GPa. The modulus is comparable with that of Steel.