ge添加对al-si系钎料合金显微组织和性能的影响 effects of germanium additions on microstructures and properties of al-si filler metals for brazing aluminum.pdfVIP

Trans. Nonferrous Met. Soc. China 26(2016) 775−782 Effects of germanium additions on microstructures and properties of Al−Si filler metals for brazing aluminum Zhi-wei NIU, Ji-hua HUANG, Shu-hai CHEN, Xing-ke ZHAO School of Materials Science and Engineering, University of Science and Technology Beijing, Beijing 100083, China Received 18 June 2015; accepted 17 November 2015 Abstract: A series of Al−Si−Ge filler metals were studied for brazing aluminum. The microstructures and properties of the filler metals were investigated systematically. The results show that the liquidus temperature of Al−Si−Ge filler metals drops from 592 to 519 °C as the content of Ge increases from 0 to 30% (mass fraction). As the content of Ge increases, bright eutectic Ge forms. However, as the Ge content exceeds 20%, the aggregation growth of the eutectic structure tends to happen and coarsened primary Si−Ge particle forms, which is detrimental to the properties of alloys. The Al− 10.8Si− 10Ge filler metal has good processability and wettability with the base metal Al. When this filler metal is used to braze 1060 aluminum, the complete joint can be achieved. Furthermore, the shear strength test results show that the fracture of brazed joint with Al− 10.8Si− 10Ge filler metal occurs in the base metal. Key words: Al−Si−Ge filler; microstructure; brazed joint; shear strength; 1060 aluminum disadvantage was the high content of zinc, which caused 1 Introduction the dissolution of the aluminum substrate. Similar to