Effect of Quenching Rate on Microstructure and Hardness of Al-Zn-Mg-Cu-Cr Alloy Extruded Bar

Autor: HAN Su-qi, LIU Sheng-dan, LI Cheng-bo, LEI Yue, DENG Yun-lai, ZHANG Xin-ming
Jazyk: čínština
Rok vydání: 2017
Předmět:
Zdroj: Cailiao gongcheng, Vol 45, Iss 4, Pp 9-14 (2017)
Druh dokumentu: article
ISSN: 1001-4381
DOI: 10.11868/j.issn.1001-4381.2015.000502
Popis: The effect of quenching rate on microstructure and hardness of Al-Zn-Mg-Cu-Cr alloy extruded bar was studied by hardness test, scanning electron microscopy and transmission electron microscopy. The results show that at quenching rate below 100℃/s, during the cooling process, the hardness begins to fall significantly; and it decreases by 43% at the quenching rate of 2℃/s. At quenching rate below 100℃/s, the number and size of equilibrium η phase heterogeneously nucleated at(sub)grain boundaries and on dispersoids inside grains increase obviously with the decrease of quenching rate, leading to greatly reduced age-hardening response. At the same quenching rate, the equilibrium η phase inside grains is larger than that at grain boundaries. In the range of the studied quenching rates, a quantitative relationship between hardness and equilibrium η phase area fraction has been established.
Databáze: Directory of Open Access Journals