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采用末端淬火和中断淬火方式,结合透射电镜(TEM),研究了6082铝合金的淬火特性及微观组织变化特征。结果表明:在末端淬火试验条件下,6082铝合金的淬透深度为15~20 mm;淬火敏感区间的平均冷却速率达20℃/s时,合金时效后形成细小弥散的β″相,无沉淀析出带(PFZ)窄小。在中断淬火的高温保温过程中,几乎没有β平衡相的析出,时效后获得了较高的硬度;在中温保温过程中,β平衡相因消耗周围的溶质原子而快速形成并长大,导致时效后合金性能大幅度下降;低温保温过程中,β平衡相形成缓慢,随时间增加,析出数量增多并长大,影响后续时效强化效果。合金在慢冷和保温过程中,析出的β平衡相大多是以富铁相颗粒作为不均匀形核的核心,这是造成合金淬火敏感性高的原因之一。
The quenching characteristics and microstructure changes of 6082 aluminum alloy were studied by means of end quenching and interrupting quenching combined with transmission electron microscopy (TEM). The results show that the quenching depth of 6082 aluminum alloy is 15 ~ 20 mm under the condition of quenching test. When the average cooling rate of quenching sensitive zone is up to 20 ℃ / s, the fine β ’ There is almost no precipitation of β equilibrium phase during the quenching and high temperature heat preservation process, and high hardness is obtained after aging. During the medium temperature heat preservation process, the β equilibrium phase consumes the surrounding solute atoms Rapid formation and growth, resulting in a substantial decline in alloy performance after aging; low temperature insulation process, the formation of β equilibrium phase slow, with increasing time, precipitation increased and grow up, affecting the subsequent aging strengthening effect of the alloy in the slow cooling and thermal insulation process , The precipitation of β equilibrium phase mostly iron-rich phase particles as the core of the uneven nucleation, which is caused by high quenching sensitivity of the alloy one of the reasons.