(1. 北京科技大學(xué) 材料科學(xué)與工程學(xué)院，北京 100083；
2. 機(jī)械科學(xué)研究總院 先進(jìn)制造技術(shù)研究中心，北京 100083；
3. 北京有色金屬研究總院，北京100088)
摘 要: 在保護(hù)氣氛中采用噴射成形制備技術(shù)制備了形狀完整的AZ91鎂合金沉積圓柱坯。對沉積坯進(jìn)行顯微組織分析，結(jié)果表明：噴射沉積AZ91鎂合金具有均勻、細(xì)小的等軸晶組織，平均晶粒尺寸約17 μm，有效地改善了離異共晶β-Mg17Al12相在晶界的偏析；擠壓變形過程引發(fā)的動態(tài)再結(jié)晶使噴射成形AZ91鎂合金的組織進(jìn)一步細(xì)化；經(jīng)175 ℃時效時，析出相中多數(shù)為不連續(xù)析出，連續(xù)析出所占比例很小；后期階段時效過程加快，長時間時效未見片狀及針狀析出物球化現(xiàn)象。噴射成形AZ91 鎂合金經(jīng)擠壓變形和T6處理后，抗拉強(qiáng)度和屈服強(qiáng)度分別達(dá)到435和360 MPa，伸長率為9.2%，實現(xiàn)了強(qiáng)度和韌性的同步大幅度提高。
關(guān)鍵字: AZ91鎂合金；噴射成形；顯微組織；力學(xué)性能
high strength AZ91 Mg alloy by spray forming technology
（1. School of Materials Science and Engineering, University of Science and Technology Beijing,
Beijing 100083, China;
2. Advance Manufacture Technology Center, China Academy of Machinery Science and Technology,
Beijing 100083, China;
3. Beijing General Research Institute for Nonferrous Metals, Beijing 100088, China）
Abstract:AZ91 magnesium preform with complete shape was prepared using spray forming technology under protective atmosphere. The microstructure analysis shows that AZ91 Mg alloy has homogeneous and equiaxial-grains structure, the average grain size is 17 μm. The segregation tendentiousness of divorce eutectic β-Mg17Al12 phase towards the grain boundary is greatly improved. The further grain refinement is attributed to the dynamic recrystallization during extrusion processing. When aging at 175 ℃, two kinds of precipitates exist which are the majority of lamellar discontinuous precipitates and a small amount of dispersive continuous precipitates. During the latter aging, β-Mg17Al12 phase precipitates quickly and no spheroidized lamellar is observed. The average tensile ultimate, yield strength and elongation of the sprayed AZ91 Mg alloy after extruded T6 treatment are 435 MPa, 360 MPa and 9.2%, respectively, at the room temperature, which indicates a better combination of toughness and strength.
Key words: AZ91 magnesium alloy; spray forming; microstructure; mechanical property
