Alvant undertakes high-precision CNC machining

IN THE FAMILY AMCs are not a single material but a family of materials. Tis means their stiffness, strength, density, thermal and electrical properties can be tailored with particle-reinforcement or continuous-fibre- reinforcement (CFR) for applications where higher performance is needed. To manufacture CFR-AMCs, Alvant uses

a preform – a three-dimensional fabric form designed to precisely conform to a specific shape and to meet exact mechanical and structural requirements. Elements of Alvant’s innovative manufacturing process, advanced liquid pressure forming (ALPF), are the subject of patents. In addition to using continuous- fibre materials for reinforcement, to achieve certain physical and mechanical properties the company can also use its Intellectual Property to develop particle or fibre ‘whisker’ reinforced AMCs.

HYBRID-AMC Components are not necessarily manufactured entirely from aluminium matrix composite if they have regions of low stress where enhanced mechanical properties are not required. In such cases, components can be reinforced locally in a method known as hybrid-AMC. Reinforcements are provided precisely where needed by using aluminium matrix composites as inserts inside the larger cast for the aluminium component. Tis limits the fibre content, simplifies the AMC insert geometry, and reduces costs. AMCs are suitable for applications

where conventional metals are expected to approach or exceed their performance limits. Advantages of using AMCs rather than unreinforced metals include greater strength, higher stiffness, reduced weight,

better wear resistance and a lower coefficient of thermal and electrical conductivity. Tese characteristics mean that AMCs provide the longitudinal strength of steel at one-third of the weight. AMCs also offer significant weight and performance benefits over other conventional unreinforced materials such as common alloys. Advantages of using AMCs rather than polymer-fibre reinforced materials such as carbon composites, include higher transverse strength and stiffness, better temperature capabilities, no moisture absorption, fire resistance, improved damage tolerance, and easier repairability. AMCs’ strengths in the x-, y- and z-axes, as well as giving performance advantages, also allow greater freedom in design. AMCs are suitable where they can meet the engineered component’s performance requirements, or address concerns about the likely need for repairs.

WHERE ARE THEY USED? AMCs’ product benefits mean they have potential uses in a wide range of engineering applications. It is in defence, aerospace and other forms of transport where AMCs will likely be applied in the largest quantities, but AMCs are equally suitable for high-end consumer products which need to be light, strong and capable of sustaining damage– products such as mobile devices, biomechanical prosthetics, wheelchairs, prams, bicycles and luggage, to give just a few examples. Where safety and reliability are essential,

AMCs are well suited to products such as high-pressure seals, aircraft landing gear and

seats. Where performance and precision are vital, AMCs can benefit products such as robotics, metrology machines, electric motors, automotive suspensions and sports equipment. And because AMCs are capable of withstanding extreme temperatures, they are suitable for components in high-voltage battery systems, unmanned aerial vehicles that fly at high altitudes, and vehicle powertrains.

THE ADVANTAGEOUS MATERIAL PROPERTIES AMCs have a number of advantages over alternative materials that might be considered for the same types of application. Tey are a good 50% stiffer than carbon fibre (unidirectional carbon- epoxy composite) in the longitudinal direction, and close to three times as strong in the transverse direction. AMCs retain their properties at high temperatures, unlike carbon fibre, making them better suited to high service temperature components in applications such as internal combustion engines. AMCs have much higher damage tolerance than high strength aluminium alloys and similar fatigue strength to steel. Tey also have similar fatigue response to steel. Tis means AMC components could replace high stress, high cycle steel components for a significant weight saving. If AMC components do get damaged while in use, they are more impact-tolerant than carbon fibre, meaning that they retain more performance after damage.

Comparison of AMC properties versus four relevant metals and composite materials 33

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