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Fatigue Strength and Fracture Mechanisms in Intermetllic Compound Particlate-Reinforced

金属间化合物颗粒增强材料的疲劳强度和断裂机制

基本信息

批准号：
06650081
负责人：
KATAGIRI Kazumune
金额：
$ 1.22万
依托单位：
IWATE UNIVERSITY
依托单位国家：
日本
项目类别：
Grant-in-Aid for General Scientific Research (C)
财政年份：
1994
资助国家：
日本
起止时间：
1994 至 1995
项目状态：
已结题

来源：
https://kaken.nii.ac.jp/en/grant/KAKENHI-PROJECT-06650081/
关键词：
Fatigue Strength Fatigue Crack Propagation Variable Stressing Elevated Temperature Metal Matrix Composites Die Casting NiAl Particle Ni_3Al Particle アルミニウム合金体積分率空洞析出物

项目摘要

Through the evaluation on static mechanical properties and fatigue characteristics as well as the microscopiic observations, it has been revealed that the intermetalic compund, NiAl and Ni_3Al, particle-reinforced Al die cast are superior to the SiC reinforced one as is shown in the followings.1. The endurance limit increases by reinforcement at room temperature. While the endurance limit ofmatrix die cast and SiC particle reinforced one decrease with temperature rise, reinforcement is effective at 200ﾟC in the NiAl and up to 300ﾟC in Ni_3Al particle. The endurance limit and fatigue life-time increase with increase in the particle volume fraction in all temperature ranges examined. Although these characteristics basically corresponds to that of 0.2% proof stress, suppression of local slip by the intermetalic compound particles together with precipitates such as Al_3Ni significantly contribute the fatigue strength at low stress.2. Fatigue crack initiates at voids located near the surfac … More e which are introduced on casting in all die casts. Crack propagates through the matrix and along the particle-matrix interface, and the former is dominant at elevated temperatures. No cracking in Ni_3Al particle is found.3. Fatigue crack propagation resistance of 2.5 vol% NiAl particle reinforced die cast is higher at near threshold region than the matrix and SiC reinforced one. It decreases when the particle volumefraction increase beyond 2.5%. In the crack propagation rate range of Paris rule or beyond it, 2.5 vol% NiAl particle reinforced die cast has higher crack propagation resistance while SiC has such low resistance as that in the matrix : These characteristics dose not coinside with that of fracture toughness.4. NiAl particle reinforce die cast has excellent fatigue characteristics against the two stage (low-high and high low) varying stress fatigue. Acceleration of fatigue crack propagation under intermittent oversrtressing and its microscopic mechanism in the intermetalic compound particle reinforced die cast is open problem. Less

通过静态力学性能和疲劳性能的评价以及微观观察，发现金属间化合物NiAl和Ni_3Al颗粒增强Al压铸件比SiC颗粒增强Al压铸件有上级的优越性.在室温下，通过增强提高疲劳极限。基体压铸和SiC颗粒增强压铸的疲劳极限随温度的升高而降低，NiAl在200 ℃时增强有效，Ni_3Al颗粒在300 ℃时增强有效。在所有温度范围内，疲劳极限和疲劳寿命随着颗粒体积分数的增加而增加。虽然这些特性基本上相当于0.2%的屈服应力，但金属间化合物颗粒与Al_3Ni等析出相共同抑制局部滑移对低应力下的疲劳强度有显著贡献.疲劳裂纹在靠近表面的空隙处萌生 ...更多信息 e在所有压铸件中的铸造时引入。裂纹在基体中和沿着颗粒-基体界面扩展，在高温下前者占主导地位。Ni_3Al颗粒没有开裂. 2.5vol%NiAl颗粒增强压铸件的疲劳裂纹扩展阻力在门槛值附近高于基体和SiC增强压铸件。当颗粒体积分数超过2.5%时，其值减小。在巴黎准则及以上的裂纹扩展速率范围内，2.5vol % NiAl颗粒增强压铸件具有较高的抗裂纹扩展能力，而SiC颗粒增强压铸件的抗裂纹扩展能力与基体中的SiC颗粒增强压铸件的抗裂纹扩展能力相当，这与断裂韧性的特性不一致. NiAl颗粒增强压铸件具有良好的抗高低两级变应力疲劳性能。金属间化合物颗粒增强压铸件在间歇过应力作用下疲劳裂纹扩展的加速及其微观机理是一个尚未解决的问题。少