Preparation Of Tin-based And Copper-based Alloy Metal By Gas Atomization

In the recent years, amorphous alloy attracted much attention because of their excellent mechanical properties, magnetic properties, electrical properties, etc. Cu₄₆Zr₄₂Al₇Y₅ is a typical example of Cu-base amorphous materials with advantages of high strength, high hardness and resistance to acid attack, so it looks like with a bright future material. Gas atomization is often used to prepare metal and alloy powder, it is also a kind of effective way to obtain amorphous alloy. However, the preparation of amorphous alloy is difficult to succeed since it needs large cooling rate and low oxygen content atmosphere. Through continuous attempts, the design of crucible, nozzle and powder collector have been determined, so as to realize the construction of the equipment. The arm of this research is to build a set of simple and feasible gas atomization equipment to prepare alloy powder and amorphous alloy successfully, moreover, do some research about the alloy powder and amorphous alloy.This article explore influence of the different process parameters, and the results show that 150 ℃ superheat is best, with increasing of gas pressure tends to achieve finer powder and inner diameter of delivery tube has a little influence on particle size distribution. Spherical copper-tin compound powder is also prepared in this article, and XRD suggests that powder phase contains Cu₆Sn₅, Cu3 Sn and Sn. The morphology and inner microstructure of copper-tin particles show obvious size effect. After further improvement of atomization equipment, amorphous, partial crystalline and crystalline Cu₄₆Zr₄₂Al₇Y₅ alloy have been prepared, then to analysis their mechanical properties with the means of nano indentation and Vickers hardness. Results show that the hardness of amorphous alloy is minimum, and that of crystalline alloy is maximum. Nano indentations load-displacement curve of amorphous alloy exist maximum number of serration flow. Three samples tested by Vickers observed under SEM suggests that amorphous and partial crystalline alloy emerge shear band, crystalline alloy shows none shear band. Further experiment has been done to analysis the influence of close pressure on the appearance and disappearance of shear band. On the microstructure, amorphous alloy looks flat, partial crystalline and crystalline alloy looks rough, and partial crystalline is rougher. On the fracture morphology, amorphous alloy appears river pattern, which belongs to cleavage mode. Partial crystalline alloy appears large concave structure and a small amount of cleavage fracture, which belongs to inter granular and cleavage fracture mode. Crystalline alloy appear more obvious river pattern and a small amount of concave structure, which belongs to cleavage and inter granular fracture mode. All the three states Cu₄₆Zr₄₂Al₇Y₅ alloy are brittle fracture.The particle size effect of copper-tin compound powder in this article has a close relationship with cooling rate and phase transformation, the detail inner mechanism still needs further research. The mechanism of amorphous alloy shear band formation and disappearance after additional energy input is worthy of further exploration.