气/液比对喷射成形超高强铝合金显微组织及性能的影响研究

Influence of G/M Ratio on Microstructures and Properties of Spray-Formed Ultra-High Strength Aluminum Alloys

采用喷射成形技术制备了Al11Zn2．8Mg1．8Cu超高强铝合金，研究了G／M比对材料显微组织及室温机械性能的影响。结果表明：喷射成形沉积坯件微观组织均匀、细小，晶粒基本为球形或类球形，T相和S相数量大幅度减小（与铸造相比）；随着G／M比的增大，喷射成形沉积坯件的晶粒尺寸逐渐减小，低熔点共晶相的数量也逐渐减少，但收得率逐渐降低。研究结果表明理想的G／M值为4．5～5．0kg／kg，此时晶粒度为15～25μm，致密度可达到94％～96％，收得率可以达到60％～65％，极限抗拉强度为800～830MPa，同时延伸率在9％以上。

The Al11Zn2.8Mg 1.8Cu ultra-high strength aluminum alloy was prepared by spray forming technology, and the influence of G/M ratio on microstructures and properties of alloys was studied. The resuits show that the microstructures of the alloy are homogeneous and the grains are spherical or approximate spherical morphology with an average grain size of 10 to 50μm. The secondary phase along the grain boundary and inside the grain is fine, and the micro-segregation and macro-segregation are restrained in the alloy. The increase of the G/M ratio leads to refinement in grain size, decrease in the amount of phase S .and T, decrease in yield, improvement in room temperature mechanical properties. When the G/M ratio ：is 4.5 - 5.0, the grain size is 15- 25μm, the density is 94% - 96%, the ultimate tensile strength of the alloy is 800 N 830 MPa, and the elongation rate is above 9%, after T6 heat treatment.