Impeding effect of the Al3(Er,Zr,Li) particles on planar slip and intergranular fracture mechanism of Al-3Li-1Cu-0.1Zr-X alloys
Impeding effect of the Al3(Er,Zr,Li) particles on planar slip and intergranular fracture mechanism of Al-3Li-1Cu-0.1Zr-X alloys
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DOI：
10.1016/j.matchar.2018.10.023
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发表时间：
2019
影响因子：
4.7
通讯作者：
T. Yu;Bingcheng Li;A. Medjahed;L. Hou;R. Wu;Jinghuai Zhang;Jianfeng Sun;Milin Zhang
中科院分区：
文献类型：
--
作者：
T. Yu;Bingcheng Li;A. Medjahed;L. Hou;R. Wu;Jinghuai Zhang;Jianfeng Sun;Milin Zhang
研究了Al-3Li-1Cu-0.1Zr-xEr (x=0, 0.1)合金的显微组织和力学性能。添加0.1wt% Er后，出现弥散的核壳结构Al3(Er,Zr,Li)颗粒，并抑制了再结晶。此外，还观察到绕过Al3(Er,Zr,Li)颗粒的位错痕迹。本文通过比较不同强化机制的理论值与屈服强度，也验证了Orowan机制是Al3(Er,Zr,Li)颗粒的主要强化机制。结果表明，Al3(Er,Zr,Li)颗粒对Al3Li剪切引起的平面滑移具有阻碍作用，这也对应于添加Er后合金中塑性不稳定性的消失。时效56h的Al-3Li-1Cu-0.1Zr-0.1Er合金具有较好的极限抗拉强度(306MPa)和屈服强度(235MPa)。有趣的是，与不含Er的合金相比，这种具有不明显平面滑移的合金表现出较低的延伸率（9.4%）和明显的晶间断裂。为了研究这种特定现象，研究了晶粒内部和晶界的硬度。结果表明，该合金的沿晶断裂是由晶粒内部比晶界更高的强度引起的，而传统的平面滑移机制的影响并不明显。
The microstructure and mechanical properties of Al-3Li-1Cu-0.1Zr-xEr (x = 0, 0.1) alloys were investigated. With an addition of 0.1 wt% Er, dispersive core-shell structure Al3(Er,Zr,Li) particles were presented and the recrystallization was restrained. Besides, the trace of dislocations bypassing the Al3(Er,Zr,Li) particles was observed. Herein, the Orowan mechanism was also verified as the main strengthening mechanism of the Al3(Er,Zr,Li) particles by comparing the theoretical value in different strengthening mechanisms with the yield strength. The result demonstrated the impeding effect of the Al3(Er,Zr,Li) particles on the planar slip induced by shearing of the Al3Li, which also corresponded to the disappearance of the plastic instability in the alloy with Er addition. The Al-3Li-1Cu-0.1Zr-0.1Er alloy aged for 56 h possessed better ultimate tensile strength of 306 MPa and yield strength of 235 MPa. Interestingly, this alloy with unremarkable planar slip manifested lower elongation of 9.4% and obvious intergranular fracture when compared to the alloy without Er. To study this specific phenomenon, the hardness of grain interior and grain boundaries was investigated. The result showed that the intergranular fracture of this alloy was induced by higher strength of the grain interior than that of the grain boundaries, while the effect of the traditional planar slip mechanism was not apparent.