Fatigue life improvement of TC11 titanium alloy by novel electroshock treatment
Fatigue life improvement of TC11 titanium alloy by novel electroshock treatment
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DOI：
10.1016/j.matdes.2022.110902
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发表时间：
2022-07
期刊：
影响因子：
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通讯作者：
Yanli Song;Z. Wang;Yongqing Yu;Wenlin Wu;Zhongmei Wang;Jue Lu;Qian Sun;Lechun Xie;L. Hua
中科院分区：
文献类型：
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作者：
Yanli Song;Z. Wang;Yongqing Yu;Wenlin Wu;Zhongmei Wang;Jue Lu;Qian Sun;Lechun Xie;L. Hua
为了提高钛合金的使用寿命，提出了一种新型的低频、交变脉冲、有限能量密度的电击处理（EST）方法。研究了不同工艺参数对TC 11合金疲劳寿命的影响。试验结果表明，采用适当的EST，合金的低周疲劳寿命提高了22.5%。利用SEM和TEM研究了影响疲劳寿命的机理。结果表明，适当的挤压变形后，α相的体积分数增加，板条状转变的β相被局部破碎溶解，并伴随着第二次α相的形成，其形貌由片状转变为更细分散的针状。结果表明，适当的EST可导致纳米级的固态相变，即不稳定的脆性AlTiHx相在合金基体中溶解，并在β相中析出尺寸接近5 nm的Al24Ti8强化相。当记录的样品的局部最高温度仅为296.8 °C时，这些转变发生。综上所述，EST工艺对钛合金的微观组织演变和纳米级相变显著提高了疲劳寿命。
To improve the service life of titanium alloys, a novel electroshock treatment (EST) with low frequency, alternating pulse, and limited energy density is proposed in this study. The effects of different parameters process on the fatigue life of TC11 alloy were investigated. Experimental data show that low-cycle fatigue life of the alloys increased 22.5% by the appropriate EST. The mechanism affecting the fatigue life was studied by SEM and TEM. The results show that after the appropriate EST, the volume fraction of the α phase increased, the lath-like transformed β phase was broken and dissolved locally, accompanied by the formation of a secondary α phase and its morphological transformation from flake-like to more finely dispersed acicular. It was found that the appropriate EST led to the nanoscale solid-state phase transition; namely, the dissolution of an unstable brittle AlTiHxphase in the alloy matrix and precipitation of the Al24Ti8strengthening phase with a size close to 5 nm in the β phase. These transitions occurred when the local maximum temperature of the sample recorded was only 296.8 °C. In summary, the microstructural evolution and nanoscale phase transformation of titanium alloy by the EST process significantly increased the fatigue life.