Above 882oC, zirconium has a BCC crystal structure with a = 0.332 nm. Below this temperature, zirconium has an HCP structure with a = 0.2978 nm and c = 0.4735 nm. Determine the percent volume change when BCC zirconium transforms to HCP zirconium. Is that contraction or expansion?

Contraction

Explanation:

From the given information;

Above 88° C

zirconium has a BCC crystal structure with a = 0.332 nm

Below this temperature

zirconium has an HCP structure with a = 0.2978 nm and c = 0.4735 nm

the volume of BCC can now be:

the volume of HCP can now be:

Ths; the volume percent change when BCC zirconium transforms to HCP zirconium can be calculated as:

Hence; it is contraction due to what the negative sign portray, The negative sign signifies that there is contraction during cooling