Question

1. Why are components made from steel or aluminum alloy used on aircraft?

2. For each of the following suggest a part on an aircraft that needs that particular material property: hardness, strength, elasticity, placidity, ductility, toughness, and brittleness.

3. Explain in why exceeding the yield point causes permeant stain, and how that is measured and calculated.

4. What do the temperatures on 1 & 2 of the iron– Carbon phase diagram indicate, shown in the presentation? What is the difference between 3 & 5? Four (4) represents the melted region; will the composition of the alloy be the same?

Answer 1

The design of an aircraft is done by considering various factors such as efficiency, comfort, safety and reliability. As a result, the design of the aircraft has to meet specific requirements which influence the complexity of its structure and the materials used in its construction. Many materials can be used in the design of the aircraft to make use of properties such as strength, elasticity, specific weight and corrosion resistance, wear resistance depending upon the requirement.

The metals used in the aircraft manufacturing industry include steel, aluminium and their alloys. Aluminium is characterised by possessing lower density than steel alloys , with good corrosion resistance properties. So, we select Aluminium and it's alloys where strength is not the main criteria and weight is the criteria.

However, steel and its alloys have a greater tensile strength, as well as a higher elastic modulus. As a result, steel is used in the parts of aircraft for which strength is major issue when compared to corrosion or weight. Generally steel is used in the design of landing gears.