Material Properties: Crystal Structure, Density, Hardness

• Crystal structure is the arrangement of atoms in different patterns.
• The arrangement of multiple unit cells together is called a crystal lattice.
• A unit cell represents the geometry of atomic arrangement.
• In a simple cubic structure, there are 8 total atoms.
• Density is defined as mass per unit volume of a material.
• Thermal conductivity is the ability of a metal to transmit heat throughout its mass.
• Specific gravity is the ratio of the density of a material to the density of water.
• Strength is the ability of a material to deform under tensile load.
• Malleability is the ability of a material to be flattened into thin sheets under applications of heavy compressive forces without cracking.
• Plasticity is the ability of a material to undergo irreversible or permanent deformations without breaking or rupturing.
• Elasticity is the ability of a material to return to its original size and shape when stress is removed.
• Hot Hardness is the ability of a material to resist softening at high temperature
• Malleability is the ability to undergo a large permanent deformation in compression.
• Creep is slow plastic deformation of metals under constant stress at high temperature.
• Ferrous material has iron as its main constituent.

Amorphous vs Crystalline Materials

• Rubber is an amorphous material.
• Glass, Rubber, and Plastic are amorphous materials.
• Steel is a crystalline material.
• Crystalline materials have a definite arrangement in crystal structure.

Brittle vs Ductile Materials

• Ceramics are brittle materials.
• Cast iron and Glass are brittle materials.
• Low carbon steel and Aluminum are ductile materials.

Material Properties

• Hardness is the ability to withstand surface indentation and scratching.
• Toughness is the ability of a material to absorb shocks and vibrations.
• Fatigue failure is the failure of material at a lower stress due to repetitive or fluctuating stress.
• Durability is the ability to withstand wear, pressure, or damage.
• Plasticity is the ability of a material to undergo irreversible or permanent deformations.
• Elasticity is the ability of a material to return to its original size and shape when the stress is removed.
• Strength is the ability of a material to resist stress without failure.

Solid Solutions

• An interstitial solid solution is when solute atoms fill holes between solvent atoms.
• A substitutional solid solution is when solute atoms replace some of the solvent atoms.
• Brass is an example of substitutional solid solution.
• Brass is an alloy of copper and zinc.
• Bronze is an alloy of copper and tin.
• Pure metals are elements that consist of a single type of atom.
• The percentage of carbon in steel varies from 0.08 to 2.
• The percentage of carbon in cast iron varies from 2 to 6.67.

Iron-Carbide Diagram Reactions

• The eutectoid reaction on an iron-carbide diagram occurs at 0.8% carbon.
• The peritectic reaction on an iron-carbide diagram occurs at 0.18% carbon.
• The eutectic reaction on an iron-carbide diagram occurs at 4.3% carbon.
• The percentage of carbon in hypo-eutectoid steel varies from 0.08 to 0.8.
• The percentage of carbon in hyper-eutectoid steel varies from 0.8 to 2.
• The percentage of carbon in hypo-eutectic cast iron varies from 2 to 4.3.
• The percentage of carbon in hyper-eutectic cast iron varies from 4.3 to 6.67.
• In an iron-carbide equilibrium diagram, austenite is stable only above 727 degrees Celsius.
• In an iron-carbide equilibrium diagram, cementite changes from ferromagnetic to paramagnetic at 210 degrees Celsius temperature.
• In an iron-carbide equilibrium diagram, ferrite changes from ferromagnetic to paramagnetic at 768 degrees Celsius temperature.
• Pearlite is the mixture of ferrite and cementite.
• Ferrite has a BCC (Body-Centered Cubic) crystal structure.
• Austenite has an FCC (Face-Centered Cubic) crystal structure.
• Cementite has an orthorhombic crystal structure.
• Ledeburite is the eutectic mixture of Austenite and Cementite.

Hardness Testing

• In the Brinell hardness test, the indenter used has a ball diameter of 10 mm.
• The load applied for testing iron and steel in the Brinell hardness test is 3000 kg.
• The load applied for testing nonferrous metals in the Brinell hardness test is 500 kg.
• The Brinell hardness test works on the principle of measuring the area of indentation.
• The Rockwell hardness test works on the principle of measuring the depth of indentation.
• In the Rockwell hardness test, the minor load applied is 10 kg.
• In the Rockwell hardness test, the hardness number is read directly from the dial.
• In the Rockwell hardness test, the ball indenter uses red numbers on the dial.
• In the Rockwell hardness test, the brale (diamond cone) indenter uses black numbers on the dial.

Explore material properties like crystal structure, density, and hardness. Learn about crystal lattices, unit cells, and their arrangements. Understand concepts like thermal conductivity, specific gravity, malleability, plasticity, and elasticity.