Answer:
Metals have high melting points thus unlikely to degrade when temperatures increase, they can be fabricated and are cost effective due to availability.
Explanation:
Aluminum is the most abundant in the Earth's crust with good thermal and electric properties. It is soft, malleable ,ductile and lighter making it a vital metal in construction industry. An alloy of copper and tin, bronze is a better connector of heat and electricity ,commonly used in automobile industry for bearings and springs production. Steel a carbon alloy has applications in forging and automotive.
Explanation:
Conduction:
Heat transfer in the conduction occurs due to movement of molecule or we can say that due to movement of electrons in the two end of same the body. Generally, phenomenon of conduction happens in the case of solid . In conduction heat transfer takes places due to direct contact of two bodies.
Convection:
In convection heat transfer of fluid takes place due to density difference .In simple words we can say that heat transfer occur due to motion of fluid.
Answer:
(a) Surface energy is greater than grain boundary energy due to the fact that the bonds of the atoms on the surface are lower than those of the atoms at the grain boundary. The energy is also directly proportional to the number of bonds created.
(b) The energy of a high-angle grain boundary is higher than that of a small-angle grain boundary because the high-angle grain boundary has a higher misalignment and smaller number of bonds than a small-angle grain boundary.
Explanation:
(a) Surface energy is greater than grain boundary energy due to the fact that the bonds of the atoms on the surface are lower than those of the atoms at the grain boundary. The energy is also directly proportional to the number of bonds created.
(b) The energy of a high-angle grain boundary is higher than that of a small-angle grain boundary because the high-angle grain boundary has a higher misalignment and smaller number of bonds than a small-angle grain boundary.
