The Production of nanocrystal materials with high fatigue damage resistance based on clarification of non-scale fatigue damage mechanism

基于阐明非尺度疲劳损伤机理的高抗疲劳损伤纳米晶材料的制备

• 批准号: 15360056
• 负责人: SUGETA Atsushi
• 金额: $ 8.58万
• 依托单位: Osaka University
• 依托单位国家: 日本
• 项目类别: Grant-in-Aid for Scientific Research (B)
• 财政年份: 2003
• 资助国家: 日本
• 起止时间: 2003 至 2005
• 项目状态: 已结题
• 来源: https://kaken.nii.ac.jp/grant/KAKENHI-PROJECT-15360056/
• 关键词: Nano-scale; Fatigue damage; Pre-plastic working; Fatigue crack growth rate; Crack closure; Powder metallurgy; Microscale observation; Life prediction; 変動荷重

Fatigue crack growth tests were carried out using CT specimens of ultra-fine grained P/M (Powder Metallurgy) aluminum alloy of which grain size was from 200 to 500 nm. Fatigue crack growth behavior was investigated under constant amplitude and repeated two-step variable amplitude load sequences. It was found that roughness induced crack closure played an important role in closure behavior of this material. Although the roughness of fracture surface was smaller than the other conventional aluminum alloys, the roughness induced crack closure was dominant because of the small crack tip opening displacement (CTOD) with respect to the roughness level. Under repeated two-step loading, crack opening load was lower than that under constant amplitude loading with the same K value as the high level load, and the crack growth retardation caused by load history was not prominent comparing with other aluminum alloys. It is considered that the crack opening load under variable amplitude loading was … More dominated by the roughness induced crack closure. The small contribution of the plasticity induced crack closure was due to the constraint of plastic strain by the grain boundaries of ultra-fine grains.Small fatigue crack initiation and growth behavior at elevated temperatures were investigated using ultra-fine grained P/M (Powder Metallurgy) aluminum alloy of which grain size was from 200 to 500 nm. Reversed plane bending fatigue tests were conducted at three different temperatures of room temperature (R.T.), 200℃ (473K) and 250℃ (523K), and crack initiation and small crack growth were studied in detail by means of replication technique. The fatigue strength decreased as test temperature increased. The cracks initiated at the boundary between powders regardless of test temperatures, and total fatigue life was dominated by crack initiation life. The fatigue crack initiation and growth behavior was almost irrelevant to the test temperatures. Fatigue crack growth rates, da/dn, were slightly accelerated at a fixed Kmax with increasing test temperature, while da/dn evaluated in terms of Kmax/E (E : Elastic modulus) agreed well. The dependence of fatigue strength and crack growth rate on test temperature was much smaller than that of conventional aluminum alloys, indicating the high heat resistance of ultra-fine grained P/M aluminum alloy. Less

对晶粒尺寸为200 ~ 500 nm的超细晶粉末冶金铝合金CT试样进行了疲劳裂纹扩展试验。研究了恒幅和两步变幅载荷序列下的疲劳裂纹扩展行为。结果表明，粗糙度引起的裂纹闭合对该材料的闭合行为起着重要作用。虽然断裂表面的粗糙度小于其他传统的铝合金，粗糙度引起的裂纹闭合占主导地位，因为小裂纹尖端张开位移（CTOD）相对于粗糙度水平。在两步重复加载条件下，裂纹张开载荷低于等幅加载条件下的裂纹张开载荷，且与其它铝合金相比，加载历史对裂纹扩展的阻滞作用并不显著。本文认为变幅载荷下的裂纹张开载荷是 ...更多信息 由粗糙度引起的裂纹闭合主导。研究了晶粒尺寸为200 ~ 500 nm的超细晶粉末冶金（Powder Metallurgy，PM）铝合金高温疲劳小裂纹萌生和扩展行为。在室温（R.T.），200℃（473 K）和250℃（523 K）时，裂纹的萌生和小裂纹的扩展。疲劳强度随试验温度的升高而降低。裂纹萌生于粉末之间的边界处，而与试验温度无关，总疲劳寿命主要由裂纹萌生寿命决定。疲劳裂纹的萌生和扩展行为与试验温度几乎无关。疲劳裂纹扩展速率，da/dn，略有加速，在一个固定的Kmax随着试验温度的增加，而da/dn的Kmax/E（E：弹性模量）方面的评价一致。疲劳强度和裂纹扩展速率对试验温度的依赖性远小于常规铝合金，表明超细晶铝合金具有较高的耐热性。少

项目成果

超微細結晶粒P/Mアルミニウム合金の2段繰返し変動荷重化における疲労き裂進展特性

两步循环变载荷下超细晶粉末冶金铝合金疲劳裂纹扩展特性

• 发表时间: 2004
• 期刊: 日本機械学会M&M2004材料力学カンファレンス講演論文集 No.04-6
• 作者: 比田井 洋史;戸倉 和;ATSUSHI SUGETA;戸倉和;菅田 淳;菅田 淳;菅田 淳;菅田 淳
• 通讯作者: 菅田 淳

The Effect of Pre-plastic Working on Fatigue Crack Growth Behavior in Ultra-fine Grained P/M Aluminum Alloys

预塑性加工对超细晶粉末冶金铝合金疲劳裂纹扩展行为的影响

• 发表时间: 2006
• 期刊: Transactions of the Japan Society of Mechanical Engineers, Series.A 73-5(in press)
• 作者: Shinji Tanimura;菅田 淳;Shinji Tanimura;ATSUSHI SUGETA
• 通讯作者: ATSUSHI SUGETA

超微細結晶粒P/Mアルミニウム合金の中高温域における微小疲労き裂発生および初期進展挙動

超细晶粉末冶金铝合金中高温区微疲劳裂纹萌生及初始扩展行为

• 发表时间: 2006
• 期刊: 材料 55-6
• 作者: K.Sato;N.Imanaka;K.Fukui;M.Numao;S.Kyotani;K.Yashiro;T.Kawada;T.Hashida;J.Mizusaki;菅田 淳
• 通讯作者: 菅田 淳

超微細結晶粒P/Mアルミニウム合金の変動荷重化における疲労き裂進展挙動

变载荷下超细晶粉末冶金铝合金疲劳裂纹扩展行为

• 发表时间: 2004
• 期刊: 日本機械学会関西支部第79期定時総会講演論文集 No.044-1
• 作者: 比田井 洋史;戸倉 和;ATSUSHI SUGETA;戸倉和;菅田 淳;菅田 淳;菅田 淳
• 通讯作者: 菅田 淳

超微細結晶粒P/Mアルミニウム合金の中高温域における微小疲労き裂発生および初期進属挙動

超细晶粉末冶金铝合金在中高温范围内的微疲劳裂纹萌生和初始扩展行为

• 发表时间: 2006
• 期刊: 材料 55・6(印刷中)
• 作者: Shinji Tanimura;菅田 淳
• 通讯作者: 菅田 淳