FORMATION OF GLOBULAR STRUCTURES IN ALUMINUM A۳۵۶ ALLOY BY NARROWMELT STREAM (NMS) TECHNIQUE

Abstract: structures in alloys. This method is based on pouring the melt through a small sized nozzle into a mould located at acertain height under the crucible. This simple method generates globular structures without using equipments such asimpellers, electromagnetic stirrers, ultrasonic probes and cooling slopes. Therefore it is cost effective. In the presentstudy, the effect of casting size and mould casting modulus on the globular structure evolution in A۳۵۶ aluminium alloyspecimens prepared by NMS process was investigated. The results showed that regardless of the different castingmodulus and their sizes, all the specimens exhibited globular structures. However, the size and shape factor of theglobules decreased with increased casting modulus and casting size indicating the influential effect of the surface areaof the mould in generating globular structures in this process.Narrow Melt Stream (NMS) is a relatively new semisolid metal processing technique for producing globular