Materials Science and Engineering最新文献

Toughness and microstructural factors of Ti6Al4V alloy Ti6Al4V合金的韧性及显微组织因素

Materials Science and Engineering Pub Date : 1988-04-01 DOI: 10.1016/0025-5416(88)90238-8

M Niinomi, T Kobayashi, N Sasaki

{"title":"Toughness and microstructural factors of Ti6Al4V alloy","authors":"M Niinomi, T Kobayashi, N Sasaki","doi":"10.1016/0025-5416(88)90238-8","DOIUrl":"10.1016/0025-5416(88)90238-8","url":null,"abstract":"<div>The instrumented Charpy impact test, the dynamic fracture toughness test and the static fracture toughness test using the DC electrical potential method were carried out on Ti6Al4V alloys. Ti6Al4V alloys with various microstructures were used to investigate the relation between microstructural factors, including fractographic measurements, and various toughness criteria, i.e. Charpy absorbed energies (Et, total absorbed energy; Ei, apparent crack initiation energy; Ep, apparent crack propagation energy); dynamic fracture toughness Jd; static fracture toughness (JIc (EPM), by DC electrical potential method or KQ); static fracture propagation resistance curve (JR curve); and static tearing modulus Tmat.The toughness of the Ti6Al4V alloy as evaluated by the Charpy test was different from that given by the dynamic toughness test mainly because the microstructural unit which controlled the fracture was different in the different tests. The toughness evaluated by means of the JR curve or Tmat does not always coincide with that given by JIc (EPM). Therefore it is necessary to use an appropriate toughness criterion that corresponds to the method of design. It was found that the microstructure had a greater influence on Tmat than on JIc (EPM). In addition, the relationships between microstructural factors (i.e. the areal fraction of the primary α phase, the mean free path in the primary α, the depth of dimples, the prior β grain size) and the various toughness criteria mentioned above must be clearly defined.</div>","PeriodicalId":100890,"journal":{"name":"Materials Science and Engineering","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"1988-04-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://sci-hub-pdf.com/10.1016/0025-5416(88)90238-8","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"74667065","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

引用次数: 25

Aging and partial austenitizing of age-hardenable CrNiMo steels of the type 10-10-2 and 6-11-3 10-10-2和6-11-3型时效硬化CrNiMo钢的时效和部分奥氏体化

Materials Science and Engineering Pub Date : 1988-04-01 DOI: 10.1016/0025-5416(88)90251-0

K. Macek, J. Pluhar, J. Cejp

引用次数: 3

Line tension model of the interaction between dislocations and extended obstacles to glide 位错与扩展障碍物相互作用的线张力模型

Materials Science and Engineering Pub Date : 1988-04-01 DOI: 10.1016/0025-5416(88)90244-3

U. Messerschmidt

{"title":"Line tension model of the interaction between dislocations and extended obstacles to glide","authors":"U. Messerschmidt","doi":"10.1016/0025-5416(88)90244-3","DOIUrl":"10.1016/0025-5416(88)90244-3","url":null,"abstract":"<div>Within the framework of the line tension model, the “force-distance” relation is calculated for dislocations cutting extended obstacles to their glide. The treatment is based on the determination of the Gibbs free energy of activation Δ G, and includes consideration of “chemical” terms which refer to the creation of structural disorder, line energy terms which refer to the changing lengths of the dislocation inside and outside the particle and the work done by the applied effective stress <math><mtext>ɹ</mtext><msup><mi></mi><mn>*</mn></msup></math>. The activation volume is obtained from the relation υ = −∂ΔG/∂τ*. It turns out to be the absolute value of the Burgers vector multiplied by the total area swept by the dislocation in the particle and in the matrix during the activation event. In this paper an attempt is made to clarify the concept of the “activation distance” for extended obstacles, which in the literature is either ignored or treated incorrectly. Some examples are calculated for a rhomboidal cutting plane and different types of interaction.</div>","PeriodicalId":100890,"journal":{"name":"Materials Science and Engineering","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"1988-04-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://sci-hub-pdf.com/10.1016/0025-5416(88)90244-3","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"75034618","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

引用次数: 2

Structure formation and interdiffusion in vacuum plasma sprayed CoNiCrAlY coatings on IN738LC IN738LC真空等离子喷涂CoNiCrAlY涂层的组织形成与相互扩散

Materials Science and Engineering Pub Date : 1988-04-01 DOI: 10.1016/0025-5416(88)90258-3

B. Gudmundsson, B.E. Jacobson

{"title":"Structure formation and interdiffusion in vacuum plasma sprayed CoNiCrAlY coatings on IN738LC","authors":"B. Gudmundsson, B.E. Jacobson","doi":"10.1016/0025-5416(88)90258-3","DOIUrl":"10.1016/0025-5416(88)90258-3","url":null,"abstract":"<div>The MCrAlY-type alloys used as overlay coatings have proved successful in a variety of gas turbine applications in protecting against oxidation and hot corrosion. Since the properties and behaviour of the coatings are related to the microstructure, it is essential to investigate structure formation during deposition, superalloy heat treatment and service. In this study the phase transformations during heat treatment and aging in the CoNiCrAlY-IN738LC system were investigated. The CoNiCrAlY coatings were produced by vacuum plasma spraying (VPS) in a full-scale production unit and subsequently vacuum heat-treated (at 1120°C for 2 h and at 845°C for 24 h) and aged in air at 850°C for up to 500 h. The microstructural features were revealed by scanning and transmission electron microscopy and the diffusion profiles were determined by energy dispersive X-ray analysis.In the as-deposited condition, the CoNiCrAlY coating has a dual-phase structure of β-NiAl (B2, ordered body-centred cubic) and γ (face-centred cubic). As a consequence of interdiffusion during heat treatment at 1120°C, a three-phase equilibrium, γ + γ′ + β, forms in the interface region between the CoNiCrAlY coating and the substrate. Furthermore, yttria (Y2O3) and chromium carbides (M23C6) are present as dispersed particles in the CoNiCrAlY coating. It is proposed that phase transformations during heat treatment of the CoNiCrAlY-IN738LC system can be predicted by using the simplified NiCoAl three-phase equilibrium diagram.</div>","PeriodicalId":100890,"journal":{"name":"Materials Science and Engineering","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"1988-04-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://sci-hub-pdf.com/10.1016/0025-5416(88)90258-3","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"81129655","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

引用次数: 20

Temperature-induced alterations of the structure and mechanical properties of cork 温度对软木结构和机械性能的影响

Materials Science and Engineering Pub Date : 1988-04-01 DOI: 10.1016/0025-5416(88)90240-6

M.Emília Rosa , M.A. Fortes

引用次数: 40

Cyclic stress—strain response of polycrystalline copper under fatigue conditions producing enhanced strain localization 疲劳条件下多晶铜的循环应力-应变响应产生增强的应变局部化

Materials Science and Engineering Pub Date : 1988-04-01 DOI: 10.1016/0025-5416(88)90239-X

Zhirui Wang, Campbell Laird

引用次数: 74

Effect of distribution of grain boundary diffusivity on plastic flow of austenitic steel I: Characterization of microstructure. Determining the distribution of grain boundary diffusivity 晶界扩散率分布对奥氏体钢塑性流动的影响I:显微组织表征。确定晶界扩散系数的分布

Materials Science and Engineering Pub Date : 1988-04-01 DOI: 10.1016/0025-5416(88)90242-X

W.A. Swiatnicki, M.W. Grabski

引用次数: 10

Effect of prolonged high-temperature exposure on the fatigue and fracture behavior of aluminum-lithium alloy 2090 长时间高温暴露对2090铝锂合金疲劳断裂行为的影响

Materials Science and Engineering Pub Date : 1988-04-01 DOI: 10.1016/0025-5416(88)90235-2

K.T Venkateswara Rao, R.O Ritchie

{"title":"Effect of prolonged high-temperature exposure on the fatigue and fracture behavior of aluminum-lithium alloy 2090","authors":"K.T Venkateswara Rao, R.O Ritchie","doi":"10.1016/0025-5416(88)90235-2","DOIUrl":"10.1016/0025-5416(88)90235-2","url":null,"abstract":"<div>Effects of prolonged exposures of 100–1000 h at 163°C on fatigue crack propagation and fracture toughness behavior have been studied in commercial aluminum-lithium alloy 2090-T8E41, and results compared with behavior in similarly over-aged 2124 alloy. Over-aging in 2090, which led to decreases in strength and toughness principally through the formation of plate-like copper-rich grain boundary precipitates and associated copper-depleted and δ′ precipitate-free zones, was found to result in increased fatigue crack growth rates above ∼ 10−9 m cycle−1; near-threshold growth rates were less affected. Such behavior is related to a diminished role of crack-tip shielding during crack extension in over-aged microstructures, from less crack deflection and lower crack closure levels (from asperity wedging), arising from more linear crack paths. Despite this degradation in fatigue crack growth properties following high temperature exposure, crack growth rates in the over-aged 2090 remain comparable or superior to traditional high strength aluminum alloys, such as 2124-T351 and 7150-T651, due primarily to higher overall levels of crack-tip shielding.</div>","PeriodicalId":100890,"journal":{"name":"Materials Science and Engineering","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"1988-04-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://sci-hub-pdf.com/10.1016/0025-5416(88)90235-2","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"82161825","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

引用次数: 23

Correlation of biaxial yield behavior in copper with crystallographic texture for strains in the range 10−4–10−2 铜在10−4-10−2范围内的双轴屈服行为与晶体织构的关系

Materials Science and Engineering Pub Date : 1988-04-01 DOI: 10.1016/0025-5416(88)90234-0

J.C Bittner, B.L Adams

引用次数: 0

Time-dependent recovery of the elastic modulus in thermally shocked polycrystalline yttrium iron garnet (YIG) 热冲击多晶钇铁石榴石弹性模量随时间的恢复

Materials Science and Engineering Pub Date : 1988-04-01 DOI: 10.1016/0025-5416(88)90233-9

H.M. Chou, E.D. Case

引用次数: 6