Question

10. 30 0- 2000 4000 6000 8000 10000 12000 14000 16000 18000 The diagram above shows the properties of several classes of materials with a yield strength on the y-axis and density on the x-axis (a) Explain how it is possible to engineer the yield strength of a single class of metal alloys to range over several orders of magnitude. (b) Explain why the density of a single class of metal alloys does not vary greatly.

Answer 1

a. Yield strength is the stress in a particular material after which the alloy or material starts to deform plastically. The plastic deformation in a material depends on the yield strength. Generally the yield strength of a single class metal alloy is not too high to be used in several engineering works. But it can be increased by several orders of magnitude by combining different alloys. It is a quite tough and time consuming process to find out the suitability of the two alloys to work together. If the yield strength of the alloys do not vary to much, then they can be engineered to be worked together. Thus it is possible to range the yield strength of a single class metal to several orders.

b. Density of a material is mass per unit volume. It is specific for a particular type of material generally. But it may vary due to several circumstances. So for a single class metal alloy density is more or less same. Density of some alloy may vary due to temperature, pressure etc. But it can not vary greatly.