检索结果-南通市图书馆

Journal of Magnesium and Alloys 2023年第5期11卷 1592-1607页

作者： hitoshi soyama Chieko Kuji Yiliang Liao Department of Finemechanics Tohoku University6-6-01 AobaAramakiAoba-kuSendai 980-8579Japan Department of Industrial and Manufacturing Systems Engineering Iowa State University2529 Union Dr.AmesIA 50011United States of America

To investigate the improvement in the fatigue strength of magnesium alloy by peening methods,magnesium alloy AZ31 was treated by submerged laser peening(SLP),cavitation peening(CP),and shot peening(SP),and the fatigue properties were evaluated by a plane bending fatigue test.In the case of SLP,both the impact induced by laser ablation(LA)and that caused by laser cavitation(LC),which developed after LA,were used.In the present study,the fatigue life at a constant bending stress was examined to determine the suitable coverage.It was found that the fatigue strengths at N=10^(7)for the SLP,CP,and SP specimens treated by each optimum condition were 56%,18%,and 16%higher,respectively,than that of the non-peened(NP)specimen,which was 97 MPa.The key factors in the improvement of fatigue strength by peening methods were work hardening and the introduction of compressive residual stress.

关键词： Magnesium alloy Fatigue strength Laser peening Cavitation peening Shot peening

The Use of Cavitation Peening to Increase the Fatigue Strength of Duralumin Plates Containing Fastener Holes

维普期刊数据库

同方期刊数据库评论

在线全文

学校读者我要写书评

暂无评论

Materials Sciences and Applications 2014年第6期5卷 430-440页

作者： hitoshi soyama Department of Nanomechanics Tohoku University Sendai Japan

An effective method for improving the fatigue life of Duralumin plates with fastener holes, such as those used in the construction of aircraft, is to introduce a compressive residual stress around the fastener holes. Cavitation peening is a novel peening method that uses the cavitation impact produced when a high-speed water jet is injected into a water-filled chamber. In this paper, Duralumin plate specimens with holes were treated by cavitation peening under various conditions, and the fatigue strength of the specimens was determined using a plate bending fatigue test. It was revealed that a compressive residual stress was introduced not only on surfaces perpendicular to the axis of the cavitating jet but also on the walls of holes which were parallel to this. It was found that a 51% improvement in fatigue strength could be achieved by cavitation peening. Note that this is first report demonstrating an improvement in the fatigue life of Duralumin plates with fastener holes by cavitation peening.

关键词： Fatigue Fastener Hole Duralumin Cavitation Peening Residual Stress

Effect of Residual Stress on the Corrosion Behavior of Austenitic Stainless Steel

在线全文

维普期刊数据库

学校读者我要写书评

暂无评论

Advances in Chemical Engineering and Science 2015年第1期5卷 62-71页

作者： Osamu Takakuwa hitoshi soyama Department of Nanomechanics Graduate School of Engineering Tohoku University Sendai Japan

In this paper we demonstrate that the residual stress introduced by several different surface finishes affects the critical current density for passivation and the passive current density in the anodic polarization curve of austenitic stainless steel and that those critical current densities can be reduced by controlling the residual stress by applying a cavitating jet to the backs of specimens. The results show that the current density either increased or decreased depending on the surface finish, and that was decreased by introducing compressive residual stress for all surface finishes.

关键词： Residual Stress Corrosion Passive Film Plarization Stainless Seel

Optimizing the Conditions for Residual Stress Measurement Using a Two-Dimensional XRD Method with Specimen Oscillation

在线全文

维普期刊数据库

学校读者我要写书评

暂无评论

Advances in Materials Physics and Chemistry 2013年第1期3卷 8-18页

作者： Osamu Takakuwa hitoshi soyama Department of Nanomechanics Graduate School of Engineering Tohoku University Sendai Japan

In order to optimize the conditions for residual stress measurement using a two-dimensional X-ray diffraction (2D-XRD) in terms of both efficiency and accuracy. The measurements have been conducted on three stainless steel specimens in this study. The three specimens were processed by annealing, a cavitating jet in air and a disc grinder, with each method introducing different residual stresses at the surface. The specimens were oscillated in the ω-direction, representing a right-hand rotation of the specimen about the incident X-ray beam. The range of the oscillation, Δω, was varied and optimum Δω was determined. Moreover, combinations of the tilt angle between the specimen surface normal and the diffraction vector, ψ, with the rotation angle about its surface normal, f, have been studied with a view to find the most optimum condition. The results show that the use of ω oscillations is an effective method for improving analysis accuracy, especially for large grain metals. The standard error rapidly decreased with increasing range of the ω oscillation, especially for the annealed specimen which generated strong diffraction spots due to its large grain size.

关键词： Two-Dimensional XRD Diffraction Ring Oscillation Residual Stress Stainless Steel

Improvement of Fatigue Strength of Additive Manufactured Metals by Solid-Liquid-Gas Interfacial Phenomena Induced by Pulse Laser

在线全文

维普期刊数据库

学校读者我要写书评

暂无评论

Improvement of Fatigue Strength of Additive Manufactured Met...

Estimation of the Yield Stress of Stainless Steel from the Vickers Hardness Taking Account of the Residual Stress

作者： hitoshi soyama Department of Finemechanics Tohoku University

Although additive manufactured（AM） metals are attractive materials, the fatigue strength of AM metals are considerably weak comparing with that of wrought materials. The mechanical surface treatment such as shot peening can improve the fatigue strength of metallic materials. Recently, a novel mechanical surface treatment using solid-liquid-gas interfacial phenomena induced by pulse laser has been developed. In the present paper, in order to demonstrate the improvement of fatigue strength of AM metals by solid-liquid-gas interfacial phenomena, titanium alloy Ti6Al4V manufactured by electron beam melting EBM was treated by submerged pulse laser and tested by a plane bending fatigue test. The key factors were investigated by evaluating the relation between the fatigue properties and mechanical properties of the surface treated by submerged laser peening, cavitation peening and shot peening.

关键词：

来源： cnki会议评论

在线全文

cnki会议

学校读者我要写书评

暂无评论

Journal of Surface Engineered Materials and Advanced Technology 2013年第4期3卷 262-268页

作者： Osamu Takakuwa Yusuke Kawaragi hitoshi soyama Department of Nanomechanics Graduate School of Engineering Tohoku University Sendai Japan.

In this paper, a method that uses the Vickers hardness to estimate the yield stress of a metallic material with taking account of residual stress is proposed. Although the yield stress of bulk metal can be evaluated by a tensile test, it cannot be applied to local yield stress varied by surface modification methods, such as the peening technique which introduces high compressive residual stress at the surface. Therefore, to evaluate the local yield stress employing a relatively easy way, the Vickers hardness test was conducted in this paper. Since the Vickers hardness depends on both the residual stress and the yield stress, the relationship between the residual stress and the Vickers hardness was experimentally examined. It was concluded that the yield stress of the surface treated by several peening techniques can be estimated from the Vickers hardness once this has been corrected for residual stress.

关键词： Peening Yield Stress Hardness Residual Stress

Movement of Dislocations in the Sub-Surface of a Polycrystalline Metal by Cavitation Peening Observed by Transmission Electron Microscopy

在线全文

维普期刊数据库

学校读者我要写书评

暂无评论

Materials Sciences and Applications 2015年第2期6卷 140-144页

作者： Osamu Takakuwa Akihiko Chiba hitoshi soyama Department of Nanomechanics Graduate School of Engineering Tohoku University Sendai Japan Institute for Materials Research Tohoku University Sendai Japan

The impact produced when cavitation bubbles collapse can be utilized to modify surfaces in the same way as shot peening and it is called cavitation peening (CP). CP is one of a number of surface modification techniques used to improve the fatigue strength of metallic materials by introducing compressive residual stress. Although it has been shown by an X-ray diffraction method that CP decreases the micro-strain related to dislocations in the sub-surface of a polycrystalline material, the mechanism for this decrease is unclear. In this paper, the movement of dislocations by CP was observed using transmission electron microscopy (TEM).

关键词： Microstructure Transmission Electron Microscopy Dislocation Surface Modification Cavitation

Using Cavitation Peening to Improve the Fatigue Life of Titanium Alloy Ti-6Al-4V Manufactured by Electron Beam Melting

在线全文

维普期刊数据库

学校读者我要写书评

暂无评论

Materials Sciences and Applications 2016年第4期7卷 181-191页

作者： Mitsuru Sato Osamu Takakuwa Masaaki Nakai Mitsuo Niinomi Fumio Takeo hitoshi soyama Department of Nanomechanics Graduate School of Engineering Tohoku University Sendai Japan Institute for Materials Research Tohoku University Sendai Japan Department of Mechanical Engineering Hachinohe National College of Technology Hachinohe Japan

Although Electron Beam Melting (EBM) is an innovative technology, the fatigue properties of materials manufactured by EBM may be lower than those of casted and wrought materials due to defects and surface roughness. In order to enhance the fatigue life of components or structures manufactured by EBM, a mechanical surface treatment technology, e.g., peening, would be effective because peening introduces high compressive residual stress at the surface which can extend the fatigue life considerably. In the present study, specimens were manufactured by EBM using titanium alloy Ti-6Al-4V powder. Two types of specimens were prepared: as-built and as-machined specimens. Specimens of each type were treated by cavitation peening or shot peening. The fatigue lives of the specimens were evaluated by a plate bending fatigue tester. The residual stress and surface roughness were also evaluated. The results obtained showed that the fatigue strength of as-built specimens can be improved by 21% by cavitation peening or shot peening, and the fatigue life under particular applied stresses can also be extended by 178% by cavitation peening.

关键词： Component Electron Beam Melting Ti-6Al-4V Cavitaion Peening Residual Stress Fatigue

Introduction of Compressive Residual Stress by Means of Cavitation Peening into a Titanium Alloy Rod Used for Spinal Implants

在线全文

维普期刊数据库

学校读者我要写书评

暂无评论

Materials Sciences and Applications 2013年第7期4卷 23-28页

作者： Osamu Takakuwa Amrinder S. Gill Gokul Ramakrishnan Seetha R. Mannava Vijay K. Vasudevan hitoshi soyama Department of Nanomechanics Tohoku University Sendai Japan School of Dynamic Systems University of Cincinnati Cincinnati USA

The introduction of compressive residual stress is an effective way to reduce fretting fatigue and fretting wear between a spinal implant rod and its holding fixture. The objective of this paper is to demonstrate that cavitation peening can introduce compressive residual stress into the surface of a spinal implant rod manufactured from medical grade titanium alloy Ti-6Al-4V, which has already been processed by glass shot peening. In order to apply the cavitation peening for the small rod, whose diameter is only 5.5 mm, the cavitating region was concentrated by increasing the ambient pressure. The depth profiles of the resulting residual stress were evaluated by X-ray diffraction following layer removal by electropolishing. The results show that cavitation peening creates compressive residual stress deeper into the rod, even though the stress value at the near surface is saturated due to initial processing using glass shot peening. The depth of the compressive residual stress continuously increases from 44 μm to 230 μm with an increase in the cavitation peening processing time. In addition, the full width at half maximum value of the X-ray diffraction profile, which is closely related to the micro-strain, decreases by up to 32% following the application of cavitation peening.

关键词： Compressive Residual Stress Fretting Titanium Alloy Cavitation Peening Spinal Implant Rod