Investigation of the quenching sensitivity of forged 2A14 aluminum alloy by time-temperature-tensile properties diagrams
Investigation of the quenching sensitivity of forged 2A14 aluminum alloy by time-temperature-tensile properties diagrams
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DOI：
10.1016/j.jallcom.2017.09.041
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发表时间：
2017-12
影响因子：
6.2
通讯作者：
Yuxun Zhang;Yin Youping;Hua Shiquan;D. Fei;Huimin Wang
中科院分区：
文献类型：
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作者：
Yuxun Zhang;Yin Youping;Hua Shiquan;D. Fei;Huimin Wang
为了指导锻造2A14铝合金的淬火工艺设计，用时间-温度-拉伸性能(TTP)图研究了该材料的淬火敏感性。TTP图是通过间断淬火试验和拉伸试验确定的。用透射电子显微镜和能谱分析观察了显微组织。结果表明，淬火敏感性温度范围为300~390℃，鼻部温度约为350℃，抗拉强度和屈服强度在淬火敏感性温度范围内迅速下降，且在鼻部温度下降最快。此外，随着等温保温时间的延长，屈服强度的下降速度快于抗拉强度的下降速度。在350C的鼻尖温度下，由于溶质的高扩散速率和高的相形核速率，淬火诱导的棒状θ‘粒子迅速析出和长大。随着保温时间的延长，棒状θ颗粒的数量和尺寸增加。这一增加导致淬火后过饱和固溶体减少，从而降低了针状细小时效诱导析出相θ‘和θ“(强化颗粒)的密度，并增加了时效处理后无沉淀区的宽度。
To guide the design of quenching technologies for forged 2A14 aluminum alloys, the quenching sensitivity of this material was investigated with time-temperature-tensile properties (TTP) diagrams. The TTP diagrams were determined by interrupted quenching experiments followed by tensile testing. The microstructures were observed with TEM and EDX. The results indicate that the quenching sensitivity temperature range is from 300 to 390 °C and the nose temperature is about 350 °C. The tensile strength and yield strength decrease rapidly in the quenching sensitivity temperature range, and they decrease most rapidly at the nose temperature. In addition, the yield strengths decrease faster than the tensile strengths with increasing isothermal holding times. At the nose temperature of 350 °C, quench-induced rod-shaped θ′ particles precipitate and grow rapidly because of the high diffusion rate of the solute and the high phase-nucleation rate. The amount and size of the rod-shaped θ′ particles increase when the holding time is prolonged. This increase results in a decrease of supersaturated solid solution after the quenching, which reduces the density of the needle-shaped fine age-induced precipitates θ′ and θ″ (strengthening particles) and increase the breadth of precipitate free zone (PFZ) after the aging treatments.