(中南大學(xué) 材料科學(xué)與工程學(xué)院，長(zhǎng)沙 410083)
摘 要: 為了探明2124合金的淬火后室溫停留效應(yīng)對(duì)合金力學(xué)性能的影響并找到應(yīng)對(duì)措施，運(yùn)用拉伸試驗(yàn)、硬度試驗(yàn)、電導(dǎo)率測(cè)試、DSC測(cè)試、XRD實(shí)驗(yàn)、EDS、TEM實(shí)驗(yàn)手段對(duì)2124合金淬火后室溫停留不同時(shí)間的力學(xué)性能、相變過(guò)程及顯微組織進(jìn)行分析。結(jié)果表明：合金淬火后室溫停留降低2124合金隨后185 ℃人工時(shí)效的峰值強(qiáng)度，屈服強(qiáng)度最大降低60 MPa，伸長(zhǎng)率略有升高，但低于1.5%；室溫停留階段合金內(nèi)部析出物為GPB區(qū)，并且位錯(cuò)密度降低；室溫停留24 h后185 ℃人工時(shí)效階段主要強(qiáng)化相S相的析出激活能由淬火后直接時(shí)效的56.8 kJ/mol上升至72.7 kJ/mol，室溫停留階段位錯(cuò)密度的降低抑制了S相的非均勻析出是導(dǎo)致S相析出激活能升高的原因之一；在淬火后對(duì)材料進(jìn)行3%冷變形即可消除室溫停留對(duì)2124合金強(qiáng)度、硬度帶來(lái)的不利影響。
關(guān)鍵字: 2124合金；力學(xué)性能；淬火后室溫停留；S相
（School of Materials Science and Engineering, Central South University, Changsha 410083, China）
Abstract:To figure out the effects and reason of room temperature delay of 2124 alloy, and to find a countermeasure, mechanical property tester, hardness and electrical conductivity tests, DSC, XRD, EDS and TEM tests were used to analyze the mechanical property, phase transformation and microstructure of 2124 alloy. The result indicates that, the room temperature delay significantly reduces the intensity of 2124 alloy under followed peak aging at 185 ℃ whose σ0.2 can reduce up to 60 MPa, while the increase of elongation rate is lower than 1.5%. GPB forms during the room temperature delay, meanwhile, the density of dislocation decreases. The activation energy of S phase, the main strengthening phase of 2124 alloy under peak aging at 185 ℃, increases from 56.8 kJ/mol of alloy as-quenched to 72.7 kJ/mol of alloy as-delayed for 24 h at room temperature. The decrease of the density of dislocation, which restrains the inhomogeneous formation of S phase, is one of the reasons which result in this increase. 3% pre-deformation can eliminate the side effect of room temperature delay on 2124 alloy.
Key words: 2124 alloy; mechanical property; room temperature delay; S phase
