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通过末端淬火、差示扫描量热仪(DSC)、扫描电镜(SEM)、透射电镜(TEM)、X线衍射仪(XRD)、光学显微镜(OM)和硬度等分析测试方法研究Al-8.0Zn-2.0Mg-1.6Cu铝合金的淬透性及淬火冷却过程中的微观组织演变。研究结果表明:随着冷却速度的降低,试样的硬度显著下降,其淬透深度约为40 mm,临界冷却速度约为3.8℃/s;淬火冷却过程中平衡态MgZn2(η)相析出是影响该合金淬透性的主要因素,其析出温度区间为438～215℃;平衡态MgZn2相在淬火冷却时先后经历晶界与晶粒内部2个过程的析出,析出峰值温度分别为387℃和342℃。
The microstructures of Al-8.0Zn alloy were studied by means of end quenching, differential scanning calorimetry (DSC), scanning electron microscopy (SEM), transmission electron microscopy (TEM), X-ray diffraction (XRD), optical microscope (OM) Hardenability of -2.0Mg-1.6Cu Aluminum Alloy and Microstructure Evolution During Quenching and Cooling. The results show that with the decrease of cooling rate, the hardness of the sample decreases significantly, the depth of penetration is about 40 mm and the critical cooling rate is about 3.8 ℃ / s. The precipitation of equilibrium MgZn2 (η) phase during quenching is The main factors affecting the hardenability of the alloy, the precipitation temperature range of 438 ~ 215 ℃; equilibrium MgZn2 phase quenching and cooling process has undergone two grain boundary and grain precipitation process, the precipitation temperature were 387 ℃ and 342 ° C.