Question

Assignment Details Aluminium alloys are very widely used in the industry as structural metals, second only to steel. Pure aluminium is very soft, light in weight and low melting point which makes it quite popular for various applications. However, adding alloying elements to aluminium enhances various physical properties making it even stronger and versatile for numerous engineering applications. Answer the following questions 1. Identify the following information for pure aluminium: Atomic number Atomic mass Atomic radius Crystal structure Density Periodic table classification 2. Identify the eight most common alloy series for aluminium. 3. Explain the principle alloying element that is added in each of the series, and the main physical property achieved due to the addition of this element in each series. 4. Explain the term age hardening, and identify three aluminium alloys that are commonly used for age hardening process. 5. Identify three advantages of age hardening process in aluminium alloys. 6. Chromium in stainless steel reacts with oxygen to form a protective layer called chromium oxide; identify the protective layer formed on aluminium to protect it from corrosion. Explain how this protective layer on aluminium behaves differently as compared to iron rust. 7. Explain the terms substitutional alloys and interstitial alloys. Provide two examples for each type of alloys. 8. Explain the importance of atomic radius of alloying elements in substitutional alloys and interstitial alloys. 9. Explain the terms nucleation and grain growth in metals, and how does it differ in annealing and quenching heat treatment processes? 10. Compare the below mentioned physical properties of pure aluminum with respect to an aluminum alloy (any one) from four different series: Density (kg/m) Tensile Strength (MPa) Elastic Modulus (GPa) Material Pure Al Series xxx Series xxxx Series xxxx Series xxxx 11. Explain why alloys of metals are usually stronger than pure metals? 12. Explain briefly in your own words the importance of creating advanced alloys for engineering applications, and how will it shape our future?

Answer 1

1. For pure aluminium:

Atomic number=13

Atomic mass=26.98 u

Atomic radius=143 pm

Crystal structure = FCC

density = 2.69 g/cm3

Aluminum is present in 2nd row and 13th column of periodic table. It is a poor metal.

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