AlSi7MgBe合金半固态坯料制备及其触变成形

采用近液相线半连续铸造技术制备AlSi7MgBe合金半固态坯料,研究制坯工艺以及二次加热温度和保温时间对半固态浆料微观组织的影响,通过组织与性能分析对AlSi7MgBe合金的半固态触变成形性进行了研究.研究结果表明,AlSi7MgBe合金采用近液相线半连续铸造,坯料具有均匀、细小的蔷薇状组织.当二次加热温度为595℃,保温15 min时,能够得到适合于进行半固态触变成形的球化组织.对近液相线半连续铸造AlSi7MgBe合金坯料进行半固态触变成形,可以获得轮廓清晰、组织致密的成形件,成形件的组织与性能得到改善,与液态模锻工艺相比,硬度提高20%.

Semisolid Billet Preparation and Thixoforming of AlSi7MgBe Alloy

The effects of processing parameters of semi-solid billets preparation, reheating temperature and holding time on the semi-solid slurry microstructure of AlSi7MgBe alloy by liquidus semi-continuous casting were studied. And the thixoforming feasibility of semi-solid AlSi7MgBe alloy was investigated by analyzing the microstructure and properties of formed parts. The results showed that the microstructure is mainly the homogeneously fine rosette-shaped grains. The microstructure of the billets reheated at 595°C and held for 15 min are near-spherical grains suitable for semi-solid thixoforming. The semi-solid thixoformed parts of AlSi7MgBe alloy are clean-cut, compact and able to fulfill themselves through thixoforming which improves the microstructure and properties. Compared with the liquid forged castings, the hardness of SSM (semi-solid metal) forged castings is increased by 20%.