7B50-T7451铝合金板材孔挤压工艺性能研究

航空材料学报, 2011, 31(4): 45-50. doi: 10.3969/j.issn.1005-5053.2011.4.009

7B50-T7451铝合金板材孔挤压工艺性能研究

龚澎 ^1, , 郑林斌 ^2, , 张坤 ^3, , 伊琳娜 ^4, , 宋德玉 ^5,

1.北京航空材料研究院,北京100095

2.成都飞机工业(集团)有限责任公司,成都610092

3.北京航空材料研究院,北京100095

4.北京航空材料研究院,北京100095

5.北京航空材料研究院,北京100095

关键词： 7B50-T7451厚板 , 孔挤压强化 , 疲劳寿命 , 残余应力

Effects of Hole Cold-Expansion on Microstructure and Fatigue Property of 7B50-T7451 Aluminum Alloy Plate

采用挤压棒直接冷挤压的方法对7 B50-T7451铝合金厚板进行了孔挤压强化,对比分析了其孔挤压前后疲劳寿命；并与第三代高纯7050-T7451铝合金厚板孔挤压强化效果进行对比.通过扫描电镜(SEM)、透射电子显微镜(TEM)以及X射线应力(XRD)等方法,研究了两种合金的疲劳断口形貌特征、微观组织变化以及孔表层的残余应力场.结果表明,采用4％～6％的挤压量对7 B50-T7451厚板进行挤压强化可取得较好的疲劳强化效果,试件的疲劳寿命是未挤压强化前的29倍；而7050-T7451铝合金厚板疲劳寿命仅是未挤压强化的5.5倍.孔挤压后,7B50-T7451厚板在强化层产生位错缠结及残余压应力,压应力层深度约为7.3mm,最大残余压应力出现在距孔边约lmm处,应力值为387MPa.强化层内形成的位错胞状结构和残余压应力可有效延缓疲劳裂纹的扩展速率,从而提高试件的疲劳寿命.

参考文献

[1]	傅仕伟;王珉;左敦稳.冷挤压孔抗疲劳增寿机理与实验研究[J].航空工艺技术,1998(01):24-26.
[2]	X. Zhang;Z. Wang .Fatigue life improvement in fatigue-aged fastener holes using the cold expansion technique[J].International Journal of Fatigue,2003(9/11):1249-1257.
[3]	D.J.Smith;M.Priest .Fatigue crack growth from plain and cold expanded holes in aluminium alloys[J].International Journal of Fatigue,2000(3):189-203.
[4]	T. N. Chakherlou;J. Vogwell .The effect of cold expansion on improving the fatigue life of fastener holes[J].Engineering failure analysis,2003(1):13-24.
[5]	高玉魁.孔挤压强化对23Co14Ni12Cr3MoE钢疲劳性能的影响[J].金属热处理,2007(11):34-36.
[6]	CHANDAWANNICH N;SHARPE Jr W N .An experimental study of fatigue crack initiation and growth from cold worked holes[J].Engineering Fracture Mechanics,1979,1(01):609-620.
[7]	J. Liu;X.J. Shao;Y.S. Liu .Effect of cold expansion on fatigue performance of open holes[J].Materials Science & Engineering, A. Structural Materials: Properties, Misrostructure and Processing,2008(1/2):271-276.
[8]	DE MATOS P F P;MCEVILY A J .Material Analysis of the effect of cold-working of rivet holes on the fatigue life of an aluminum alloy[J].International Journal of Fatigue,2007,29(03):575-586.
[9]	E 647-88a,Standard test method for measurement of fatigue crack growth rates[S].US:ASTM,1978.
[10]	MCEVILY A J;M1NAKAWA K;NAKAMUEA N.Fracture mechanics,microstructure,and the growth of long and short fatigue cracks[A].Warrendale (PA):Metal Society AIME,1984
[11]	Ayatollahi, MR;Nik, MA .Edge distance effects on residual stress distribution around a cold expanded hole in Al 2024 alloy[J].Computational Materials Science,2009(4):1134-1141.
[12]	LAI M O;OH J T;NEE A Y C .Fatigue properties of holes with residual stresses[J].Engineering Fracture Mechanics,1993,45(05):551-557.

上一张下一张

计量

下载量()
访问量()

作者相关

文章评分

您的评分：
1

0%
2

0%
3

0%
4

0%
5

0%

材料期刊网