(湖南大學(xué) 材料科學(xué)與工程學(xué)院，長沙 410083)
摘 要: Mg-10Gd-4.8Y-0.6Zr鑄態(tài)合金經(jīng)525 ℃、16 h均勻化退火后，在500 ℃軋制成總變形量為84%的板材，軋制后在200 ℃進(jìn)行時(shí)效處理。觀察合金的微觀組織變化，并測試合金的力學(xué)性能。結(jié)果表明：軋制變形明顯細(xì)化了晶粒尺寸，軋制后組織中存在方塊相和長條狀相；軋制初期組織中存在大量孿晶，孿晶能很好地協(xié)調(diào)塑性變形，并誘發(fā)了孿生動(dòng)態(tài)再結(jié)晶；隨著軋制變形量的增大，孿晶數(shù)量減少，再結(jié)晶方式以晶界弓出形核為主。軋制T5態(tài)合金具有優(yōu)異的高溫力學(xué)性能，200、250、300和350 ℃時(shí)抗拉強(qiáng)度分別為392、381、251和112 MPa，350 ℃拉伸時(shí)伸長率達(dá)到107.0%。
關(guān)鍵字: Mg-Gd-Y-Zr合金；熱軋；微觀組織；力學(xué)性能
（School of Materials Science and Engineering, Hunan University, Changsha 410083, China）
Abstract:The as-cast Mg-10Gd-4.8Y-0.6Zr alloy sheets were rolled at 500 ℃ with 84% total reduction after being homogenized at 525 ℃ for 16 h and then aged at 200 ℃. The microstructures and mechanical properties were investigated. The results show that the grain size can be effectively refined by rolling process, cuboid-shaped phases and strip-shaped phases exist after being rolled. A mass of twins exist after initially being rolled, they can harmonize the plastic deformation and cause twinning-induced DRX. The number of twins decreases with the increase of rolling reduction and the DRX mode turns into grain boundary bulging mechanism. The rolled-T5 alloy has excellent elevated temperature mechanical properties: the tensile strength at 200, 250, 300 and 350 ℃ are 392, 381, 251 and 112 MPa, respectively, and the elongation at 350℃ can reach 107.0%.
Key words: Mg-Gd-Y-Zr alloy; hot rolling; microstructure; mechanical properties
