What is the relationship between the hardness and compositio

What is the relationship between the hardness and composition? Why? What is the relationship between the hardness and microstructure? Why? What differences do you notice in the x-ray diffraction patterns of the different samples? Would you expect annealing to have an effect on the hardness? Why or why not? BONUS: Determine the amount of the aluminum-rich phase in dendrite form and the amount of the eutectic region from the optical micrographs (do this for only one composition). Compare this with what you would expect from a \"theoretical\" analysis of phase fraction after solidification.

Solution

1.      Hardening is a process in which a metal are heated, and then kept at a temperature until all pearlite is transformed into austenite, and then it quenched in water or oil, without letting it change its shape. The heating time can be increased ensuring that the core will also be fully transformed into austenite The temperature at which austentizing takes place depends usually depends upon the carbon content in the metal used.. The microstructure of a hardened steel part is ferrite or cementite. On the other hand composition is the process in which 2 or more material which has difference chemical and physical properties, are combined to produce a material which has different properties from both the materials which are being combined. Therefore the material formed from this process is strong, light and durable than the normal material. Hence the hardness of a material formed from composition material is much better than the hardness of a material formed from hardening process, which is usually measured in BHN unit.

2. The microstructure of materials is usually defined by the number, type, shape, structure, grain size and their lattice defects. The microstructure of a material depends on physical properties such as strength, ductility, toughness, corrosion resistance and wear resistance. These properties in turn govern the application of these materials in industrial practice. However, it is difficult to relate hardness or microstructure. The microstructure and hardness produced in any steel Heat Affected Zone is usually dependent upon the upon composition and the hardenability of the steel, the grain size before transformation and the cooling rate through the transformation temperature range of the steel

3. Difference in the X-ray diffraction pattern file of the American Society for Testing is based on the data of four compounds not listed in the American Society for Testing Materials file and on four represented there