Lecture 2 – Metal & Alloys

 ACKNOWLEDGEMENT:

Figure (respectively)	Source of Figure
Figure 2a	http://www.spaceflight.esa.int
Figure 2b	http://www.spaceflight.esa.int

                                   

Need of Alloys:

The ductility and malleability of metals is of great industrial importance but sometimes this makes the metal less useful when materials of greater tensile strength or materials with other properties are needed. Therefore, alloys are made.

Alloys:

Alloys are defined as mixtures of 2 or more metals and metals and some non-metal (in minute amounts). The resulting material, the Alloy is superior than its constituent pure metals in terms of strength, and resistance to corrosion.

Table 2 introduces some alloys, their constitute metals, mixtures and the advantage of alloy over it constitutes.

Table 2:

Alloy	Constituent Elements	Advantage(s) of the Alloy
Brass	33% Zinc and 67% Copper	Brass is more malleable than both Zinc and Copper Bright Gold appearance Low melting point Corrosion resistant
Stainless Steel	87.5% Iron, 10.5% Chromium and 2% Carbon	Corrosion resistant          Shiny Silver appearance          Greater tensile strength (stronger)

Point to note: The compositions of constituent elements can be altered to yield different types of alloys having different properties. For example, different types of steel can be produced by varying the amount of Carbon in the alloy mixture.

The difference in properties between the alloy and its constitute elements, is explained by the change in physical structure of the alloy.

Figure 2a: Metal

Figure 2b: Alloy(s)

The alien or mixture particles prevent the sliding of metal layers on one another. This gives more strength and other properties to the resulting alloy.