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本文利用硬度、光学显微镜和透射电镜研究了微量Ti(0.15％)对Al-5.0Zn-1.8Mg合金的沉淀过程、临界形核温度(T′_c)和显微组织参数的影响.结果表明,微量Ti能显著细化晶粒,但无抑制再结晶和提高T′_c的能力.低温时效(T_aT′_c),Ti又有相反的作用,能使MPt显著粗化和降低硬度.但在任一时效温度(120—200℃),含Ti合金的GBP和PFZ均比无Ti合金小和窄.Ti对沉淀过程和组织参数的这种影响,可用Ti原子团参与了GP区形核和含Ti合金过剩空位浓度低的观点来说明.
In this paper, the effects of Ti (0.15%) on the precipitation process, the critical nucleation temperature (T’_c) and the microstructure parameters of Al-5.0Zn-1.8Mg alloy have been investigated by means of hardness measurement, optical microscopy and transmission electron microscopy. Trace Ti can significantly refine the grains, but does not inhibit the recrystallization and improve the ability of T’_c. Ti can inhibit the growth of MPt at low temperature (T_a T’_c), Ti has the opposite effect, can make the MPt significant coarsening and reduce the hardness.But at any aging temperature (120-200 ℃), containing Ti alloy GBP and PFZ than Ti-free alloys are small and narrow, and this effect of Ti on the precipitation process and microstructure parameters can be explained by the fact that Ti atoms participate in the nucleation of the GP region and the excess vacancy concentration of the Ti-containing alloy.