2124合金淬火后的室溫停留效應

2124合金淬火后的室溫停留效應Effect of room temperature delay on quenched 2124 alloy

為了探明2124合金的淬火后室溫停留效應對合金力學性能的影響并找到應對措施，運用拉伸試驗、硬度試驗、電導率測試、DSC測試、XRD實驗、EDS、TEM實驗手段對2124合金淬火后室溫停留不同時間的力學性能、相變過程及顯微組織進行分析。結果表明：合金淬火后室溫停留降低2124合金隨后185 ℃人工時效的峰值強度，屈服強度最大降低60 MPa，伸長率略有升高，但低于1.5%；室溫停留階段合金內部析出物為GPB區(qū)，并且位錯密度降低；室溫停留24 h后185 ℃人工時效階段主要強化相S相的析出激活能由淬火后直接時效的56.8 kJ/mol上升至72.7 kJ/mol，室溫停留階段位錯密度的降低抑制了S相的非均勻析出是導致S相析出激活能升高的原因之一；在淬火后對材料進行3%冷變形即可消除室溫停留對2124合金強度、硬度帶來的不利影響。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.

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