Explanation: Only one phase is present on the wide range of temperature in single phase alloys. So microstructure can’t be changed by heat treatment. Cold working, thermomechanical treatment and grain refining can change their properties.

Explanation: When the second phase forms a continuous network at grain boundaries, it makes material brittle. This microstructure reduces ductility, toughness and corrosion resistance of the alloy. This brittleness increases with amount of the second phase.

Explanation: Best microstructure should consist uniform distribution of second phase throughout the matrix. Presence of second phase on or along grain boundaries introduces brittleness. This causes a reduction in ductility and toughness.

Explanation: Spherical shaped second phase particles give the best mechanical properties. Flakes, nodules and plates shaped, on the other hand, act as internal notches. These reduce the toughness of a material.

Explanation: Single phase alloys have better mechanical properties than pure metals. It is due to solid solution strengthening. Electrical, thermal and formability properties of pure metals are generally higher.

Explanation: With a decrease in grain size, creep strength of material deteriorates. It is because the grain boundary area becomes weaker on high temperatures. Ductility, tensile strength and fatigue strength improve with grain refinement.

Explanation: Point defects greatly affect electrical resistivity of the material. This is a basis of doping process in semiconductors. With an increase in temperature, vacancies increase and electrical conductivity of semiconductors increases.

Explanation: Ductility is a structure sensitive property. It depends on microstructure, grain size and second phase particles’ shape. Density, melting point and specific heat are structure insensitive properties.

Explanation: Elastic modulus is a structure insensitive property. It only changes when a drastic change in composition is done. Fracture strength, yield strength and electrical conductivity are structure sensitive properties.

Explanation: With the fineness, the distribution in matrix increases. Thus these particles provide more resistance to dislocation motion and retain good tensile strength. These particles also retain good ductility.

Explanation: At elevated temperatures, two or more phase microstructures are preferred. Dispersed second phase particles provide good thermal stability. These also improve creep properties.