文档介绍：4 Synthesis, Fabrication, & 4 Synthesis, Fabrication, & Processing of MaterialsProcessing of Forming Operations of Casting of Miscellaneous techniques of metalCollege of Materials Science & EngineeringNORTH UNIVERSITY OF techniques (Fabrication techniques (制备技术制备技术)): ?The methods by which materials are formed or manufactured ponents(零件)that may be incorporated in useful products.?Necessary to subject ponent to some type of processing treatment in order to achieve the required properties.?The suitability of a material for an application is dictated by economic considerations with respect to fabrication and processing of Materials Science & EngineeringNORTH UNIVERSITY OF Forming Operations of metal??Concept:Concept: Those in which the shape of a metal piece is changed by plastic deformation (塑性变形);for example, forging (锻造), rolling (轧制), extrusion (挤压), and drawing (拉拔) mon forming techniques.??Deformation ConditionsDeformation Conditions:: The deformation must be induced by an external force or stress, the magnitude of which must exceed the yield strength (屈服强度) of the of Materials Science & EngineeringNORTH UNIVERSITY OF CHINAHot Working & Cold Working??Concept:Concept:When deformation is achieved at a temperature above that at which recrystallization (再结晶) occurs, the process is termed hot working; otherwise, it is cold of Materials Science & EngineeringNORTH UNIVERSITY OF CHINA?Hot-working operationAdvantages:Advantages:⑴Large deformations and repeat⑵requiring less deformation :Disadvantages:(1) Surface oxidation—resulting in material loss and a poor final surface finish.?Cold-working operationAdvantages:Advantages:⑴An increase in strength⑵Higher quality surface finish⑶Better mechanical properties⑷Closer dimensional control of the finished pieceDisadvantages:Disadvantages:(1) The decrease in ductility.