(1. 湖南科技大學(xué) 機(jī)電工程學(xué)院，湘潭 411201；
2. 湖南科技大學(xué) 高溫耐磨材料及制備技術(shù)湖南省國(guó)防技術(shù)重點(diǎn)實(shí)驗(yàn)室，湘潭 411201；
3. 中南大學(xué) 高等研究中心，長(zhǎng)沙 410083)
摘 要: 利用不同的熱處理制度制備T4、欠時(shí)效、峰時(shí)效和過(guò)時(shí)效4種狀態(tài)的合金，并通過(guò)恒應(yīng)力蠕變拉伸實(shí)驗(yàn)和顯微組織觀察分別對(duì)不同狀態(tài)合金在150 ℃、225 MPa和200 ℃、200MPa的蠕變行為進(jìn)行分析。結(jié)果表明：合金在150 ℃蠕變時(shí)，變形主要依靠晶內(nèi)的位錯(cuò)滑移，細(xì)小彌散分布的析出相以及固溶原子對(duì)位錯(cuò)的釘扎有利于降低合金的蠕變速率；4種合金在該蠕變條件下均經(jīng)歷較長(zhǎng)的穩(wěn)態(tài)蠕變階段，其中峰時(shí)效合金的蠕變速率最低；合金在200 ℃蠕變時(shí)，變形主要依靠晶界滑移；在蠕變過(guò)程中，峰時(shí)效態(tài)和過(guò)時(shí)效態(tài)合金中形成明顯的無(wú)沉淀析出帶，導(dǎo)致其蠕變速率顯著增加，并且?guī)缀鯖]有出現(xiàn)明顯的穩(wěn)態(tài)蠕變階段；欠時(shí)效態(tài)合金在該蠕變條件下的蠕變速率最低。
關(guān)鍵字: Al-Cu-Mg合金；蠕變行為；析出相；顯微組織
（1. College of Electromechanical Engineering, Hunan University of Science and Technology, Xiangtan 411201, China;
2. Key Laboratory of High Temperature Wear Resistant Materials Preparation Technology of Hunan Province,
Hunan University of Science and Technology, Xiangtan 411201, China;
3. Advanced Research Center, Central South University, Changsha 410083, China）
Abstract:Alloys at four different heat treatment states (T4, underaged, peakaged and overaged) were prepared, and their creep behaviors under the conditions of 150 ℃, 225 MPa and 200 ℃, 200 MPa were studied through constant-stress tensile creep experiments and microstructure observations. The results indicate that, when crept at 150 ℃, the deformation of alloys mainly depends on the dislocation slip within the grains. The pinning effect of dispersed tiny precipitates and solutes on the dislocations can decrease the creep rate of alloys effectively. All four alloys experience a long term steady creep stage and the peakaged state alloy possesses the lowest creep rate. When crept at 200 ℃, the main deformation of alloys switches to grain boundary (GB) sliding. Precipitate-free zones (PFZs) form in the peakaged and overaged state alloys during creeping, which increases the creep rate of alloys remarkably and disappears the steady creep stage of these alloys. The underaged state alloy possesses the lowest creep rate at this creep condition.
Key words: Al-Cu-Mg alloy; creep behavior; precipitate; microstructure
