【摘要】：針對(duì)不同時(shí)效制度下2A97鋁鋰合金的疲勞裂紋擴(kuò)展速率進(jìn)行了研究;并通過(guò)光學(xué)顯微鏡、透射電鏡和掃描電鏡對(duì)合金的微觀組織和疲勞斷口進(jìn)行了觀察分析。結(jié)果表明:2A97合金薄板(T3+135℃/12 h)時(shí)效態(tài)的裂紋擴(kuò)展速率最低,其次為T3,(T3+135℃/60 h)時(shí)效態(tài)的擴(kuò)展速率略低于(T3+135℃/120 h)時(shí)效態(tài),T6態(tài)的裂紋擴(kuò)展速率最高。時(shí)效制度在較低的ΔK水平下對(duì)合金的裂紋擴(kuò)展速率影響較大,而在較高ΔK水平下影響較小。δ′相及細(xì)小的T1相可以促進(jìn)共面滑移,增加滑移可逆性,降低裂尖應(yīng)力集中程度及塑性累積水平,同時(shí)使裂紋發(fā)生偏折,促進(jìn)裂紋閉合效應(yīng),提高裂紋擴(kuò)展抗力;粗大、密集的T1相及半共格的θ′相抑制共面滑移,易于造成應(yīng)力集中,降低裂紋擴(kuò)展抗力;晶界處的無(wú)沉淀析出帶(PFZ)及平衡相急劇降低晶界強(qiáng)度,極易造成沿晶開裂,使合金裂紋擴(kuò)展速率迅速提高。
[Abstract]:The fatigue crack propagation rate of 2A97 Al-Li alloy under different aging conditions was studied, and the microstructure and fatigue fracture of the alloy were observed and analyzed by optical microscope, transmission electron microscope and scanning electron microscope. The results show that the crack growth rate of 2A97 alloy sheet (T135 鈩，

本文編號(hào)：2397331