【摘要】 用电阻测定法研究了微量添加元素Mn、Zr和Cu等对Al-Zn-Mg合金GP区形成极限温度(T_GP^F)的影响。结果表明,单独加入一种微量元素对Al-5.08Zn-1.73Mg合金T_GP^F的影响不大,只能由121℃提高到125℃,但随Zn和Mg总含量的提高或混合加入的微量元素数目的增加,T_GP^F将明显提高（>135℃）。更多还原

【Abstract】 A lot of investigations on the formation of GP zone in medium strength Al-Zn-Mg alloys have already been made elaborately in earlier works. As for the additional minor elements, studies about their influence on the temperature limit of GP zone formation in such alloy system are still only a few. An attempt has been made to determine the temperature limit of GP zone formation TGPF after adding singly or together such additional minor elements as Gu, Zr, Mn and Cr in Al-Zn-Mg alloy and to discuss the effect of these elements on TGPF.Summary. Resistormetric method was applied to the investigation on the effect of additional minor elements. Experimental results are discussed and elucidated, by introducing a mechanism involving the binding energy between solute atoms and excess vacancies, as follows.1. For commercial Al-5.08 wt. %Zn-1.75 wt. %Mg ternary alloy containing 0.11 wt.%Fe and<0.1 wt.%Si, TGPF is 121℃.2. TGPF raises merely about 4℃ if adding singly Cu (0.19 wt.%) , Mn (0.48 wt.%) or Zr(0.22 wt.%) in the ternary Al-Zn-Mg alloy, while TGPF raises considerably (10℃) if adding these elements together in the same alloy, ie. adding (0.26wt. %Cu+0.21 wt. %Zr or 0.32 wt. %Cu+0.34 wt. %Mn + 0.14 wt.%Zr+0.22 wt.%Cr) in. The distinct results above are attributed to the unequal magnitudes of binding energy between different solute atoms and excess vacancies.3. The higher the total contents of Zn + Mg (wt.%) or the more the number of minor elements added together in, the higher the temperature limit TGPF. It is shown by the results in Table 3 that TGPF of tested alloys No.2-1 and No.2-2 are 156℃ and 158℃ respectively.Fig. 1 Percentage change in resistivity △ρ/ρo with aging time for variousaging temperature, alloy No. 1-1.Fig. 2 Maximum change in resistivity △ρm/ρo with aging temperature Tab. 1 Composition of tested alloys (wt.%) Tab.2 Maximum change in resistivity of various alloys Tab.3 Temperature limit of GP zone formation TGPFTab.4 Total content of Zn + Mg (at.%) and Zn/Mg ratio of different specimens更多还原