งานนำเสนอเรื่อง: "Chapter 4 Equilibrium Phase Diagrams and The Iron-Carbon system"— ใบสำเนางานนำเสนอ:
1 Chapter 4 Equilibrium Phase Diagrams and The Iron-Carbon system Kanchala Sudtachat
2 PhasesA phases is simply a form of material possessing a characteristic structure and properties.A phases has a definable structure, a uniform and identifiable chemistry.And distinct boundaries or interfaces that separate it from other different phases.
3 Equilibrium Phase Diagrams is a graphic mapping of the natural tendencies of a material or a material system.There are three primary variable to be considered: temperature, pressure and composition
4 Pressure-Temperature (P-T) diagram Diagram maps the stable form of water for various conditions.The region boundaries denote the melting and boiling point.It has important to make freeze drying.
5 Temperature-Composition (T-C) diagram At atmospheric pressure and variations more likely to occur in temperature and composition.
6 Cooling CurvesThe equilibrium phase diagram is collective presentation of cooling-curve data for an entire range of alloy compositions
7 Solubility StudiesCan ice retain some salt in a single phase solid solution?Can solid salt hold some water and remain a single-phase?How much, and does the amount vary with temperature?We called solubility limit.
9 Complete solubility in both liquid and solid states Liquidus line – เหนือเส้นนี้เป็นสารละลายในเฟสเหลวSolidus line – ด้านล่างของเส้นนี้เป็นสารละลายในเฟสของแข็งFreezing range: Between the liquidus and Solidus
10 Partial solid solubility At the point of max solubility, 183oCLead can hold up to 19.2 wt%If T is decreased, the amount of solute that can be held in solution decreased.
16 Iron-Carbon Equilibrium Diagram EutectoidEutecticPeritecticSteel, compose primarily of iron and carbon
17 Iron-Carbon Equilibrium Diagram a body-cubic solid that is stable down to 1394oC, know as delta-ferrite.From 1394oC to 912oC (FCC), know as austenite.Alpha-ferrite (BCC) below 912oC
18 Iron-Carbon Equilibrium Diagram At 1495oC, a peritectic reaction.At 1148oC, a eutectic with composition of 4.3% carbon2.11% carbon are classified by the general term cast ironAt 727oC, a eutectoid with composition of 0.77% carbon. Alloy with less than 2.11% carbon, know as steels
19 Steels and the simplified iron-carbon diagram The key transition will be the conversion of austenite to the two-phase ferrite plus carbide mixture.
20 Steels and the simplified iron-carbon diagram Pearlite (ferrite + cementite) Eutectoid composition (0.77%C)Austenite0.77%C; FCC Ferrite0.02%C; BCC + Cementite6.67%C
21 Steels and the simplified iron-carbon diagram Hypoeutectoid steels (ferrite + pearlite) less than eutectoid compositionHypereutectoid steels (cementile + pearlite) greater than eutectoid composition
22 Cast Irons อาจทำให้เกิด Graphite หรือ Cementite Iron-carbon alloys with more than 2.11%Wide variety properties.Contains iron, carbon, silicon, manganese, sulfur, phosphorousอาจทำให้เกิด Graphite หรือ CementiteGraphite form by slow coolingCementite form by fast cooling
Your consent to our cookies if you continue to use this website.