The effects of La addition on the microstructure and tensile properties of B-refmed and Sr-modified A1-1 1Si-1.5Cu-0.3Mg cast- ing alloys were investigated. With a trace addition of La （0.05wt%-0. lwt%）, the mutual ...The effects of La addition on the microstructure and tensile properties of B-refmed and Sr-modified A1-1 1Si-1.5Cu-0.3Mg cast- ing alloys were investigated. With a trace addition of La （0.05wt%-0. lwt%）, the mutual poisoning effect between B and Sr can be neutral- ized by the formation of LaB6 rather than SrB6. By employing a La/B weight ratio of 2：1, uniform microstructures, which are characterized by well refined ct-A1 grains and adequately modified eutectic Si particles as well as the incorporation of precipitated strengthening intermetal- lics, are obtained and lead to appreciable tensile properties with an ultimate tensile strength of 270 MPa and elongation of 5.8%.展开更多
The purpose of this study is to prepare a high-quality Al-11Si-1.5Cu-0.3Mg casting al oy with a good combination of strength and ductility. The microstructures of as-cast al oy were tailored by employing combined addi...The purpose of this study is to prepare a high-quality Al-11Si-1.5Cu-0.3Mg casting al oy with a good combination of strength and ductility. The microstructures of as-cast al oy were tailored by employing combined additives of Al-3wt.%B reifner, Al-10wt.%Sr modiifer and trace addition of La element. By using OM and SEM, the characteristics of the morphologies of eutectic Si particles and the fracture surfaces of the al oys after solution treatment and aging treatment were measured. The mechanical properties of the al oys after single-step or two-step solution treatment were investigated by tensile testing, and the quality of casting samples were evaluated by quality index, Q. The results indicate that the al oy with substantial y modiifed microstructures displays an improvement in mechanical properties of 270 MPa in ultimate tensile strength and 6% in elongation. After an optimized two-step solution treatment of 490oC/4h＋505oC/4h, the ultimate tensile strength and elongation can reach 346 MPa and 10%, respectively. Under the aging condition, the elongation maintains a relative high value of 5%together with the strength of about 400 MPa, which is the outstanding combination of strength and ductility.展开更多
基金supported by the Industry, Education, and Research Prospective Project of Jiangsu Province, China (No. BY2012191)the Open Research of Jiangsu Key Laboratory of Advanced Metallic Materials (No. AMM201202)
文摘The effects of La addition on the microstructure and tensile properties of B-refmed and Sr-modified A1-1 1Si-1.5Cu-0.3Mg cast- ing alloys were investigated. With a trace addition of La （0.05wt%-0. lwt%）, the mutual poisoning effect between B and Sr can be neutral- ized by the formation of LaB6 rather than SrB6. By employing a La/B weight ratio of 2：1, uniform microstructures, which are characterized by well refined ct-A1 grains and adequately modified eutectic Si particles as well as the incorporation of precipitated strengthening intermetal- lics, are obtained and lead to appreciable tensile properties with an ultimate tensile strength of 270 MPa and elongation of 5.8%.
基金financially supported by the Industry,Education,and Research Prospective Project of Jiangsu Province(No.BY2012191)the Open Research Foundation of Jiangsu Key Laboratory of Advanced Metallic Materials(No.AMM201202)
文摘The purpose of this study is to prepare a high-quality Al-11Si-1.5Cu-0.3Mg casting al oy with a good combination of strength and ductility. The microstructures of as-cast al oy were tailored by employing combined additives of Al-3wt.%B reifner, Al-10wt.%Sr modiifer and trace addition of La element. By using OM and SEM, the characteristics of the morphologies of eutectic Si particles and the fracture surfaces of the al oys after solution treatment and aging treatment were measured. The mechanical properties of the al oys after single-step or two-step solution treatment were investigated by tensile testing, and the quality of casting samples were evaluated by quality index, Q. The results indicate that the al oy with substantial y modiifed microstructures displays an improvement in mechanical properties of 270 MPa in ultimate tensile strength and 6% in elongation. After an optimized two-step solution treatment of 490oC/4h＋505oC/4h, the ultimate tensile strength and elongation can reach 346 MPa and 10%, respectively. Under the aging condition, the elongation maintains a relative high value of 5%together with the strength of about 400 MPa, which is the outstanding combination of strength and ductility.
