High cycle fatigue behavior of the in-situ TiB2/7050 composite
High cycle fatigue behavior of the in-situ TiB2/7050 composite
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DOI：
10.1016/j.msea.2015.06.023
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发表时间：
2015-07
期刊：
影响因子：
6.4
通讯作者：
Yu Ma;Zhe Chen;Mingliang Wang;Dong Chen;N. Ma;Hao-wei Wang
中科院分区：
文献类型：
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作者：
Yu Ma;Zhe Chen;Mingliang Wang;Dong Chen;N. Ma;Hao-wei Wang
研究了原位TiB 2/7050复合材料的显微组织和高周疲劳行为。结果表明，与未增强的7050合金相比，加入亚微米TiB 2颗粒后，原位TiB 2/7050复合材料的晶粒尺寸减小，弹性模量提高，屈服强度和抗拉强度提高，疲劳极限提高上级。通过疲劳试验，无论是复合材料还是未增强的合金试样，疲劳裂纹大多起源于表面附近的夹杂物。疲劳裂纹的萌生是由于位错堆积引起的应力集中所致。考虑到复合材料疲劳性能的改善，复合材料中的细晶粒和较高的弹性模量有利于这种增强。提出了亚微米TiB 2颗粒阻碍位错在夹杂物处堆积，延缓裂纹萌生的新观点，有效地提高了复合材料的疲劳性能。
The microstructure and high cycle fatigue behavior of thein-situTiB2/7050 composite were investigated in this work. The results showed that with the addition of sub-micron size TiB2particles, thein-situTiB2/7050 composite exhibited the smaller grain size, higher elastic modulus, enhanced yield strength and ultimate tensile strength, and superior fatigue limit over the unreinforced 7050 alloy. Through the fatigue tests, most of the fatigue cracks initiated at inclusions near the surface of both the composite and unreinforced alloy testing samples. The fatigue cracks initiation was induced by the stress concentration that was caused by the pileup of dislocations. In consideration of the improved fatigue properties of composites, the finer grains and higher elastic modulus in the composite were benefited to such enhancement. Critically, a new viewpoint was proposed that the submicron TiB2particles impeded dislocations from piling up at the inclusions and delayed the crack initiation there, which can improve the fatigue property efficiently in the composite.