Metal matrix composite, or MMC for short, is a composite material artificially combined with one or more metal or non-metal reinforcing phases with metal and its alloys as the matrix. Most of its reinforcement materials are inorganic non-metallic, such as ceramics, carbon, graphite and boron, etc., can also use wire. It is combined with polymer matrix composites, ceramic matrix composites and carbon/carbon composites to form a modern composite system.
It is characterized by high transverse and shear strength, good toughness and fatigue and other comprehensive mechanical properties, but also has the advantages of thermal conductivity, electrical conductivity, wear resistance, small thermal expansion coefficient, good damping, no moisture absorption, no aging and no pollution. For example, the specific strength of carbon fiber reinforced aluminum composite material is 3 ~ 4 * 107mm, and the specific modulus is 6 ~ 8 * 109mm. For example, the specific modulus of graphite fiber reinforced magnesium is 1.5 * 1010mm, and its thermal expansion coefficient is almost zero.
Metal matrix composites reinforced by category to category, such as fiber reinforced (including continuous and short cut), whisker reinforced and particle, etc., according to the different of metal or alloy matrix, and metal matrix composites can be divided into aluminum, magnesium, copper, titanium, high temperature alloys, intermetallic compound and refractory metal matrix composites, etc. Due to the high processing temperature, complex process, difficult interface reaction control, and relatively high cost of this kind of composite material, the application of maturity is far less than resin matrix composite material, and the application range is small.
Metal matrix composites and resin matrix composites have the same high strength, high modulus, it can withstand high temperature, at the same time, no combustion, no moisture absorption, good thermal conductivity, radiation resistance. It is a remarkable high-temperature material used in aerospace, which can be used as the surface material of aircraft turbine engine and rocket engine hot zone and supersonic aircraft. At present, continuous development and improvement of metal matrix composites with silicon carbide particles aluminum alloy development is the fastest. The metal matrix composite is only one-third as heavy as steel and two-thirds as heavy as titanium, similar to aluminum. It is stronger than carbon steel, similar to titanium alloy and slightly higher than aluminum alloy. Its wear resistance is also better than titanium alloy, aluminum alloy. At present, it has been used in small batch in automobile industry and machinery industry. In 5 ~ 15 years have the commercial application prospect is the automobile piston, brake parts, connecting rods, robot parts, computer parts, sports equipment and so on.
