(1. 中南大學(xué) 材料科學(xué)與工程學(xué)院，長(zhǎng)沙 410083；
2. 中南大學(xué) 教育部有色金屬材料科學(xué)與工程實(shí)驗(yàn)室，長(zhǎng)沙 410083)
摘 要: 利用力學(xué)性能測(cè)量和透射電鏡觀察等手段對(duì)軌道交通車(chē)輛大型材用7005 鋁合金熱處理特性進(jìn)行研究。結(jié)果表明：該合金在線擠壓淬火后于105 ℃時(shí)效時(shí)，隨著時(shí)效的進(jìn)行，開(kāi)始階段硬度上升很快，時(shí)效8 h后，硬度(HB)達(dá)100 HB；時(shí)效50 h后，硬度(HB)可達(dá)125 HB以上；此后隨著時(shí)效時(shí)間的延長(zhǎng)硬度上升緩慢，時(shí)效200 h后，硬度仍未達(dá)到峰值;經(jīng)(105 ℃，8 h)+(155 ℃，8 h)雙級(jí)時(shí)效后，σb=395 MPa，σ0.2=330 MPa，δ=12%，硬度為117 HB。合金在較高溫度(155 ℃和180 ℃)單級(jí)時(shí)效及雙級(jí)時(shí)效時(shí)間過(guò)長(zhǎng)，均引起析出相粒子明顯長(zhǎng)大、粗化，導(dǎo)致合金強(qiáng)度降低。
關(guān)鍵字: 7005鋁合金；熱處理特性；淬火；時(shí)效；力學(xué)性能
7005 Al alloy employed in railway trains
（1. School of Materials Science and Engineering, Central South University, Changsha 410083, China;
2. Key Laboratory of Nonferrous Metal Materials Science and Engineering, Ministry of Education,
Central South University, Changsha 410083, China）
Abstract:The heat treatment characteristic of the 7005 aluminum alloys was studied by mechanical properties measurement and TEM. The results show that, during the process of aging at 105 ℃ after on-line quenching, the hardness(HB) of alloy increases quickly at first and reach about 100 HB after aging for 8h and 125 HB after 50 h, then the hardness increases slowly with increasing aging time, and the hardness does not reach the peak value even the alloy is aged for 200 h. After aging at (105 ℃, 8 h)+(155 ℃, 8 h), the mechanical properties of 7005 aluminum alloy are σb=395 MPa, σ0.2=330 MPa, δ=12%, 117 HB. If the aging of alloy at high temperature (155 ℃, 180 ℃) or the two-stage aging is too long, the precipitated phases of the alloy will grow and coarsen, and then the alloy strength decreases.
Key words: 7005 Al alloy; heat treatment characteristic; quenching; aging; mechanical properties
