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本文研究了含Zr的高强7050铝合金中Zr化合物的存在形态,尺寸和分布特点。TEM观察表明,锭铸中的Zr以ZrAl_3初晶和固溶体两种形式存在;均匀化处理的铸锭中,球形的ZrAl_3在基体上呈共格与非共格形式弥散析出,尺寸约为10～30nμ,热轧变形后,ZrAl_3大都钉轧在位错线和小角晶界上,其形态和尺寸没有明显改变;淬火后,可观察到大量存在的亚结构和亚晶粒,球形ZrAl_3质点分布在亚晶界、晶内以及位错线上,非共格的ZrAl_3周围有η相非均质成核;与含Cr的该系合金相比较,可看到E相尺寸远大于含Zr合金中的ZrAl_3质点,而ZrAl_3周围非均质成核的η相的尺寸和数量要比E相周围的小得多;淬火后经时效和双级过时效热处理,ZrAl_3质点的形态、尺寸和分布,均无显著变化。利用上述实验结果,可以园满地解释Zr对7050铝合金细化晶粒、提高再结晶温度、降低淬火敏感性以及提高强度和抗应力腐蚀性能的作用。
In this paper, the morphology, size and distribution of Zr compounds in Zr-containing high-strength 7050 aluminum alloy were investigated. TEM observation shows that the Zr in the ingot exists in both the form of the primary and the solid solution of ZrAl_3. In the homogenized ingot, the spherical ZrAl_3 disperses in the coherent and non-coherent forms on the matrix with a size of about 10 ~ After hot rolling deformation, most of ZrAl_3 was nailed on the dislocation line and small angle grain boundaries, and its morphology and size did not change obviously. Substantial substructures and subgrains were observed after quenching. The spherical ZrAl_3 particles were distributed in the In the intergranular, intergranular and dislocations, there are η-phase heterogeneous nucleation around the non-coherent ZrAl_3. Compared with this Cr-containing alloy, the size of phase E can be seen to be much larger than that of the Zr-containing alloy ZrAl_3 particles, whereas the size and number of η phase nucleated around ZrAl_3 are much smaller than those around E phase. The morphology, size and distribution of ZrAl_3 particles after aging and two-stage overaged heat treatment Significant changes. Using the above experimental results, we can fully explain the effect of Zr on the grain refinement of 7050 aluminum alloy, increase the recrystallization temperature, reduce the sensitivity of quenching and improve the strength and stress corrosion resistance.