Study on the Hot Extrusion of AZ80 Magneisum Alloy Sheet

• Main Authors: Li-Wei Jeng, 鄭力瑋
• Other Authors: Su-Hai Hsiang
• Format: Others
• Language: zh-TW
• Published: 2007
• Online Access: http://ndltd.ncl.edu.tw/handle/rcxdk6

碩士 === 國立臺灣科技大學 === 機械工程系 === 95 === ABSTRACT This research mainly focuses on the fabrication of AZ80 magnesium alloy sheet by hot extrusion. The extrusion dies used in this paper are converging dies with semi-angles at 20°, 30° and 40°, the thickness of the fabricated sheet is 2mm.and their extrusion ratio is 35.9. Another group of the converging dies with semi-angle at 30° has an extrusion ratio of 23.94, and the thickness of the fabricated sheet is 3mm. The formability of the hot extrusion of sheets by these four groups of dies are investigated. First of all, the quality quantitative analysis of Taguchi Method is employed to analyze the effects of different process parameters (heating temperature of material, temperature of ingot container, initial extrusion speed and lubricant) on the mechanical properties and extrusion load of sheet, and discuss the difference when the same die at the same semi-angle has different extrusion ratios. The paper also investigates into the difference between the adoption of multi-speed method (MSM) and the adoption of fixed speed method in the extrusion process of AZ80 magnesium alloy sheet, and observes whether the extrusion is successful, the difference of the extrusion load and the difference of tensile strength. As to the tensile strength test of the extruded sheets, the quality quantitative analysis of Taguchi Method is employed to analyze the optimal process parameters for the acquisition of AZ80 magnesium alloy sheets. The research also uses the optimal combination of parameters to conduct confirmative experiments, compares the experimental results at different extrusion ratios, and investigates the difference between the adoption of MSM and fixed speed method in the experiments. Finally, the research observes the metallographic microstructure of the finished product, hoping to control each process parameter of the hot extrusion and fabrication of sheet, and the correlation among the mechanical properties of the finished products.