Grain structure effect on quench sensitivity of Al-Zn-Mg-Cu-Cr alloy

作者：李承波; 韩素琦; 刘胜胆; 邓运来; 张新明

来源：Transactions of Nonferrous Metals Society of China (English Edition), 2016, 26(9).

DOI：10.1016/S1003-6326(16)64319-4

• grain structure
• Al-Zn-Mg-Cu-Cr alloy
• dispersoids
• quench sensitivity

The effect of grain structure on quench sensitivity of an Al?Zn?Mg?Cu?Cr alloy was investigated by hardness testing, optical microscopy, X-ray diffraction, scanning electron microscopy, transmission electron microscopy and scanning transmission electron microscopy. The results show that with the decrease of quenching rate from 960 °C/s to 2 °C/s, the hardness after aging is decreased by about 33%for the homogenized and solution heat treated alloy (H-alloy) with large equiaxed grains and about 43%for the extruded and solution heat treated alloy (E-alloy) with elongated grains and subgrains. Cr-containing dispersoids make contribution to about 33% decrement in hardness of the H-alloy due to slow quenching; while in the E-alloy, the amount of (sub) grain boundaries is increased by about one order of magnitude, which leads to a further 10%decrement in hardness due to slow quenching and therefore higher quench sensitivity.

• 单位
  中南大学