Q1: Define Metal.
Ans: A metal is a material that is typically hard, shiny, malleable, ductile, and conducts heat and electricity well.
Q2: Define Alloy.
Ans: An alloy is a mixture of two or more elements, where at least one is a metal, to improve properties like strength, hardness, or corrosion resistance.
Q3: State four properties of metals.
Ans: Properties of metals include:
- ➔ High melting point
- ➔ Good electrical and thermal conductivity
- ➔ Malleable and ductile
- ➔ Lustrous appearance
Q4: Name any six metals.
Ans: Six metals are:
- ➔ Iron (Fe)
- ➔ Copper (Cu)
- ➔ Aluminum (Al)
- ➔ Zinc (Zn)
- ➔ Nickel (Ni)
- ➔ Lead (Pb)
Q5: State four properties of alloys.
Ans: Properties of alloys include:
- ➔ Higher strength than pure metals
- ➔ Improved corrosion resistance
- ➔ Better hardness and wear resistance
- ➔ Modified melting point
Q6: Name any six alloys.
Ans: Six alloys are:
- ➔ Steel (Iron + Carbon)
- ➔ Brass (Copper + Zinc)
- ➔ Bronze (Copper + Tin)
- ➔ Stainless Steel (Iron + Chromium + Nickel)
- ➔ Duralumin (Aluminum + Copper)
- ➔ Solder (Tin + Lead)
Q7: What is meant by B.C.C?
Ans: B.C.C (Body-Centered Cubic) is a crystal structure where atoms are located at the corners and a single atom at the center of the cube.
Q8: What is meant by F.C.C?
Ans: F.C.C (Face-Centered Cubic) is a crystal structure where atoms are located at the corners and at the center of each face of the cube.
Q9: What is meant by C.P.H?
Ans: C.P.H (Close Packed Hexagonal) is a crystal structure where atoms are arranged in a hexagonal pattern for maximum packing efficiency.
Q10: What is meant by The Solid Solution?
Ans: Solid solution is a homogeneous crystalline phase where one or more elements are completely dissolved in a metal lattice.
Q11: What is Space Lattice?
Ans: Space lattice is the three-dimensional arrangement of atoms in a crystalline solid, showing the repetitive pattern of the crystal.
Q12: State the three Space Lattices of metals.
Ans: Three common space lattices of metals:
- ➔ Body-Centered Cubic (B.C.C)
- ➔ Face-Centered Cubic (F.C.C)
- ➔ Hexagonal Close Packed (C.P.H)
Q13: What is The Crystal Structure of Metal?
Ans: The crystal structure of metal refers to the specific arrangement of atoms in a repeating pattern within the metal lattice.
Q14: Define Phase.
Ans: A phase is a homogeneous portion of a material with uniform physical and chemical properties, separated by boundaries from other phases.
Q15: Name different Phases.
Ans: Different phases include:
- ➔ Ferrite (α-iron)
- ➔ Austenite (γ-iron)
- ➔ Cementite (Fe3C)
- ➔ Pearlite (mixture of ferrite and cementite)
Q16: What is Peritectic Reaction?
Ans: Peritectic reaction is a reaction where a liquid and one solid phase combine on cooling to form a second solid phase.
Q17: State the products of Peritectic Reaction.
Ans: Products: A new solid phase is formed from the liquid and initial solid phase.
Q18: What is Eutectoid Reaction?
Ans: Eutectoid reaction is a reaction where one solid phase transforms into two new solid phases at a specific temperature and composition.
Q19: State the products of Eutectoid Reaction.
Ans: Products: Two solid phases are formed from a single solid phase (e.g., Austenite → Ferrite + Cementite).
Q20: What is Eutectic Reaction?
Ans: Eutectic reaction is a reaction where a liquid transforms into two solid phases simultaneously at a specific composition and temperature.
Q21: State the products of Eutectic Reaction.
Ans: Products: Two solid phases form directly from the liquid (e.g., L → α + β).
Q22: What is Iron Carbide?
Ans: Iron carbide (Fe3C), also called cementite, is a hard and brittle compound of iron and carbon found in steel and cast iron.
Q23: What is an Iron Carbide Diagram?
Ans: The Iron Carbide Diagram (Fe-C diagram) shows phases of iron and carbon at different temperatures and compositions, used for understanding steel and cast iron behavior.
Q24: State the importance of Iron Carbide Diagram.
Ans: Importance:
- ➔ Helps in heat treatment of steel
- ➔ Shows transformation temperatures of phases
- ➔ Guides selection of steel composition
- ➔ Predicts microstructure of steel and cast iron
Q25: What is Hypo Eutectoid Steel?
Ans: Hypo Eutectoid Steel contains less carbon than the eutectoid composition (<0.8% C) and primarily forms ferrite and pearlite upon cooling.
Q26: What is Hyper Eutectoid Steel?
Ans: Hyper Eutectoid Steel contains more carbon than the eutectoid composition (>0.8% C) and primarily forms pearlite and cementite upon cooling.
