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ZL702A铝合金构件微动疲劳寿命预测研究 总被引:1,自引:1,他引:0
目的探讨ZL702A铝合金的微动损伤机理,寻找适合的微动疲劳寿命预估模型。方法以ZL702A铝合金为研究对象,设计方足桥-试件微动模拟件进行微动疲劳实验,用4XC-PC金相显微镜观察断裂试件表面的磨损形貌,探讨微动损伤机理。建立方足桥-试件有限元模型,编程计算剪应变幅、法向正应力、相对滑移距离等微动特征参数,分别运用FS、KBM、Mc Diarmid以及Ruiz参数预测ZL702A铝合金微动疲劳寿命。结果疲劳裂纹主要在局部塑性区成核,剪切应变可以加速裂纹核的形成,疲劳裂纹增长是裂纹尖端剪切带不断聚合的过程,裂纹面上的法向应力/应变使这种聚合加速。法向载荷保持不变,随着最大轴向力的增大,微动损伤增大。4种微动疲劳寿命预估模型的结果表明,微动损伤在试件接触区边缘最大,容易萌生微动裂纹,与实验值一致。微动疲劳寿命预测结果表明,Ruiz参数预测结果与实验结果误差在2倍公差带因子范围内,最接近实验值。结论微动磨损区分为粘着区、混合区、滑移区,在混合区边界上最容易发生塑性变形,萌生微动疲劳裂纹,用Ruiz参数预测ZL702A铝合金的微动疲劳寿命是可行的。 相似文献
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为了准确预测冷轧过程组合式支承辊过盈配合面微动损伤危险位置,首先基于ABAQUS软件对辊套和辊芯装配过程以及板带冷轧过程进行数值模拟,得到了冷轧过程中组合式支承辊过盈配合面的应力分布,并提取过盈配合面对应节点位移数据基于MATLAB软件得到了微动滑移分布以及滑移轨迹,在此基础上得到了过盈装配面微动滑移速度分布,最后考虑过盈配合面平均周向应力、平均径向应力以及微动滑移速度对疲劳裂纹萌生和扩展的影响,得到了摩擦功沿轴向分布规律,并引入修正后的微动损伤评价参数Gc,基于修正后的Gc参数法预测了过盈装配面上微动损伤危险位置。 相似文献
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研究A7N01铝合金焊接接头的疲劳特性,提出基于疲劳裂纹萌生寿命的寿命预测模型。母材、热影响区和焊缝三个区域内的疲劳裂纹萌生寿命差异较小。在这三个区域内,疲劳裂纹萌生寿命与疲劳总寿命之比是一个依赖于材料的参数,对于母材、热影响区和焊缝分别为26.32%、40.21%和60.67%。提出的疲劳寿命预测模型与实验结果和Basquin’s模型预测结果吻合良好。利用扫描电子显微镜(SEM)对疲劳断口进行观察,发现焊缝区域的裂纹萌生于焊接过程中产生的光滑表面。热影响区内疲劳裂纹萌生于熔合区气孔。母材中破碎的第二相是引起疲劳裂纹的主要原因。 相似文献
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研究了应力幅值对Al-Zn-Mg合金的疲劳损伤行为的影响。对不同应力幅值下Al-Zn-Mg合金的微动疲劳寿命以及微动疲劳损伤特性进行了研究。采用宏观力学试验与微观分析相结合的方法,对Al-Zn-Mg合金的微动疲劳机理进行了探讨。结果表明,Al-Zn-Mg合金的微动疲劳寿命随应力幅值的增加呈非线性降低;Al-Zn-Mg合金的微动疲劳寿命与位移幅度值具有一定的关系。微动疲劳损伤区存在微动磨损和裂纹萌生及扩展两种破坏机制,随应力幅值的变化而产生竞争关系。微动疲劳裂纹源均形成于微动斑边缘,微动能促使微动疲劳裂纹萌生和加速扩展。 相似文献
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采用超声高频疲劳试验机进行了LC4CS铝合金实验样本容量为66的超高周疲劳寿命实验.结果表明,超高周疲劳寿命具有双峰分布特征,这一特征与疲劳裂纹的萌生点有关:较短疲劳寿命的样品的裂纹萌生于夹杂等缺陷处,而较长疲劳寿命的样品的裂纹萌生于表面.寿命分布的双峰特征使得传统的升降法不能用于确定材料的超高周疲劳的条件疲劳极限,超高周疲劳寿命的分散性远大于低周和高周疲劳寿命的分散性. 相似文献
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利用自行设计的微动疲劳实验夹具装置研究超细晶纯钛在柱面-平面接触下的微动疲劳特性,分析循环应力对其微动疲劳寿命的影响,通过观察接触区磨损和断口形貌,分析其微动损伤机制。结果表明,当法向载荷不变时,超细晶纯钛的微动疲劳寿命随着循环应力的增加而减小,比常规疲劳寿命更小。微动疲劳裂纹于接触区边缘萌生,磨损区破裂严重且附着有磨粒,在磨粒磨损作用下加速了试样的疲劳失效。断口同时呈现出疲劳形貌和微动形貌,形貌从平滑转向粗糙直至断裂,裂纹由小变大,裂纹扩展速率也逐渐增加,且在裂纹扩展区存在二次裂纹;由于受力不均在裂纹扩展区与断裂区之间存在山脊状形貌。 相似文献
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微动疲劳损伤广泛存在于各种机械接触变载荷作用的构件上,如螺栓,轴承,键槽和榫槽等.微动疲劳会加速受微动作用构件的接触处表面及表层裂纹的萌生和扩展,在微动疲劳的早期阶段裂纹生长速率较高,导致了在微动条件下金属构件过早失效,大幅度降低构件寿命.本文以LZ50车轴钢为主要研究对象,实现了在圆形和椭网形路径加载下的拉扭复合微动... 相似文献
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R. Sadeler S. Atasoy A. Arıcı Y. Totik 《Journal of Materials Engineering and Performance》2009,18(9):1280-1284
An investigation has been carried out in order to study the fretting fatigue behavior of a 2014-T6 aluminum alloy, which has
been coated with a commercial hard anodizing of approximately 20-25 μm in thickness. The hardness (HV) was significantly improved
up to about 380 after hard anodizing coating while the hardness value of original 2014-T6 was 175. Fretting reduced drastically
the fatigue life of samples in both conditions, substrate and coated conditions. The application of such a coating to the
substrate may increase the fretting fatigue life in comparison with the uncoated samples in low-stress region for rotating
bending fatigue loading while at higher stresses the effect of anodizing is reversed. This may be result from early initiation
of cracking of hard anodizing film due to high-stress concentration resulting from bulk stresses. On the other hand, the increase
in fretting fatigue life in low-stress region may be probably attributed to low coefficient of friction that prevents metal-to-metal
contact, which may result in higher fretting fatigue life because of retardation of crack initiation resulting from lower
stress concentration compared to the substrate. 相似文献
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自冲铆是轻量化材料的有效连接技术,为促进该技术的广泛应用,文中基于两组铝合金自冲铆接头,采用疲劳测试、统计方法、断口分析和X-射线能谱仪元素分析,获得接头疲劳特性和断口典型部位微观组织特征,从而对铝合金自冲铆接头疲劳性能及失效机理进行研究。结果表明,随着疲劳载荷降低,接头疲劳寿命稳定性和相对滑移量下降。由于多铆钉接头有效减小了应力集中,其疲劳强度比单铆钉接头提高了31.36%~23.14%,且多铆钉接头的疲劳寿命稳定性较高。多铆钉接头中存在首要和次要承载顺序,疲劳断裂表面为首要承载顺序所在位置。接头疲劳宏观失效模式均为下板断裂,疲劳裂纹主要萌生于铆钉管腿与下板接触部位,微振磨损区域自铆钉管腿底部向铆钉头方向生长。减缓该部位的摩擦作用,可有效延迟疲劳裂纹萌生和减缓裂纹扩展,从而提高接头疲劳寿命。 相似文献
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Effects of the temperature,slip amplitude,and contact pressure on fretting fatigue(FF) behavior of the Ti811 titanium alloy were investigated using a high frequency fatigue machine and a home-made high temperature apparatus.The fretting fatigue failure mechanism was studied by observing the fretting surface morphology features.The results show that the sensitivity to fretting fatigue is high at both 350 and 500 °C.The higher the temperature,the more sensitive to the fretting fatigue failure is.Creep is an i... 相似文献
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S. Chakravarty Ph.D. R. G. Andrews M.Eng. P. C. Painaik Ph.D. A. K. Koul Ph.D. 《JOM Journal of the Minerals, Metals and Materials Society》1995,47(4):31-35
Severe fretting damage has been observed on the pressure surfaces of fan and compressor blade dovetails/disks in an aerospace gas turbine engine. A study has been carried out to evaluate the effect of an ion implantation technique in combination with the presently used surface treatments, such as shot peening and coating, on the fretting fatigue life of titanium alloy gas turbine engine components. The results from fretting fatigue tests, residual stress measurements, and nanoindentation tests were used to quantitatively evaluate the effect of various surface treatments on the fretting fatigue life of the fan blade and disk materials. Results from microstructural characterization and analyses of elemental and phase distributions within the implanted region are used to understand the effect of ion implantation on the surface properties of the alloys. Finally, an attempt has been made to evaluate the potential for improving the fretting fatigue life of the engine components using various surface modification techniques. 相似文献
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The present work deals with the effect of relative slip on fretting fatigue behaviour of 2014 Aluminium alloy with age-hardened
conditions T4 and T6 in contact with a dissimilar mating material AISI 1045 steel, using a plane-on-plane configuration. There
are a significant number of parameters influencing fretting fatigue behaviour. Relative slip value between the specimen and
fretting pad is one of the most important factors. In the present study, the influence of relative slip was evaluated at different
cyclic stress levels by using a fretting pad with a single pad span value of 10 mm. The results show the artificial temper
T6 is more effective for improving the fretting fatigue life when compared with natural temper T4. This may be attributed
to a higher microstructural barrier to the fretting fatigue crack nucleation and initiation, due to having lower values of
relative slip with artificial temper T6. 相似文献
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S. Ganesh Sundara Raman B. Rajasekaran S. V. Joshi G. Sundararajan 《Journal of Thermal Spray Technology》2007,16(4):571-579
Cu-Ni-In coating was formulated on two substrate materials—Ti-alloy (Ti-6Al-4V) and Al-alloy (AA 6063) fatigue test specimens
using detonation gun (D-gun) spray process. Coating on both substrates was dense with low porosity, high hardness, and high
surface roughness. Relatively higher surface compressive residual stress was present at the coating on Ti-alloy specimens.
In case of the coating on Al-alloy samples, tensile residual stress was also present in some places. Uniaxial plain fatigue
and fretting fatigue experiments were conducted on uncoated and coated specimens. The detrimental effect of life reduction
due to fretting was relatively larger in the Al-alloy compared to the Ti-alloy. While Cu-Ni-In coating was found to be beneficial
on the Ti-alloy, it was deleterious on the Al-alloy substrate under both plain fatigue and fretting fatigue loading. The results
were explained in terms of differences in the values of surface hardness, surface roughness, surface residual stress, and
friction stress. 相似文献