Corrosion in Metals The destruction of metals by chemical or electro-chemical reactions with the environment is called as corrosion. Freedom of valence electrons and their conduction is responsible for corrosion in metals. Gold and platinum, the noble metals, do not corrode as they are most inactive. Products of corrosion are either porous or non-porous. These […]
Brittle & Ductile Fracture in Metals Separation of a solid into two or more parts under applied load or stress is called fracture. Depending on the type of load, fracture may be termed as tensile fracture, compressive fracture, shear fracture, fatigue fracture, creep fracture and cleavage fracture etc. However, these fractures are mainly characterized by
Composite material is a material system composed of two or more dissimilar constituents, differing in forms, insoluble in each other, physically distinct and chemically inhomogeneous. The resulting product possesses properties much different from the properties of constituent materials. Classification of Composite Materials Composite materials, also referred as composites, are broadly classified as Laminated composite Lamina
Polymerization | Processing of Plastics Materials derived from carbon are termed as organic materials. Range of organic materials is in thousands owing to vast variety of hydrocarbons and their derivatives. Organic materials may be natural or synthetic. Petroleum rubber wood coal biological fibers food etc. cotton flax are examples of natural organic materials. And oil
Ceramics are nonmetallic, inorganic, amorphous solids and are mostly metallic oxides. They have poor tensile strength, and are brittle. They can be either crystalline or noncrystalline. Many ceramics are workable in extremely low (cryogenic) temperature range, while many others are able to sustain high temperatures. Silica, silicates, NaCI, rock salt, MgO, CaF2, glasses, CsCl etc.
Chemical Heat Treatment Processes In this article I will discuss chemical heat treatment processes. (All other heat treatment processes are discussed in the previous post. This article is next part of that. So for batter understanding, also read that article.) These are: 1. Case Hardening Process (or carburising) 2. Cyniding 3. Nitriding 4. Carbo-nitriding 5.
The properties of metals and alloys can be changed by heating followed by cooling under definite conditions to make them suitable for specific applications. Accordingly steel can be hardened to resist cutting action and prevent abrasion. The rate of cooling and the manner of cooling are the controlling factors in heat treatment processes. Heat treatment
Types of Carbon Steel Carbon steels (or plain carbon steels) are ferrous metals. Percentage of carbon in them varies from about 0.05% to 2%. Accordingly they are classified as mild steel, medium carbon steel and high carbon steel. Mild steel is soft, medium carbon steel is tough, and high carbon steel is hard in comparison
Lever Rule & Ternary Phase Diagram Microstructural Changes: Refer to phase diagrams of previous post. Liquid phase first changes to solid-liquid phase, and finally to solid phase during cooling. If variation in the rate of cooling is slow to fast, say 200°C per hour to 200°C per second, different microstructures will develop. If we consider
Unary Phase Diagram Phase diagrams are important and essential tools to understand compositional concentrations of two or more elements. Phase Diagrams Definition: Plots showing relations between phases in equilibrium versus composition, pressure and temperature are called phase diagrams. These are also known as equilibrium diagrams. Temperature is plotted on ordinate (y-axis) and composition (in binary