Acta Metallurgica最新文献_第10页

Modeling of ternary site occupation in L12 ordered intermetallics L12有序金属间化合物三元占位的模拟

Acta Metallurgica Pub Date : 1989-10-01 DOI: 10.1016/0001-6160(89)90318-0

Y.P. Wu, N.C. Tso, J.M. Sanchez, J.K. Tien

引用次数: 53

Kinetics of growth and coarsening of faceted hexagonal precipitates in an f.c.c. matrix—I. Experimental observations 氟化碳基体中多面六角形析出物生长与粗化动力学[j]。实验观察

Acta Metallurgica Pub Date : 1989-10-01 DOI: 10.1016/0001-6160(89)90305-2

K.E. Rajab , R.D. Doherty

引用次数: 41

Microstructure, deformation and fracture characteristics of an Al67Ni8Ti25 intermetallic alloy Al67Ni8Ti25金属间合金的显微组织、变形及断裂特征

Acta Metallurgica Pub Date : 1989-10-01 DOI: 10.1016/0001-6160(89)90296-4

C.D. Turner , W.O. Powers, J.A. Wert

{"title":"Microstructure, deformation and fracture characteristics of an Al67Ni8Ti25 intermetallic alloy","authors":"C.D. Turner , W.O. Powers, J.A. Wert","doi":"10.1016/0001-6160(89)90296-4","DOIUrl":"10.1016/0001-6160(89)90296-4","url":null,"abstract":"<div>The microstructure and mechanical properties of Al67Ni8Ti25 have been investigated. After homogenization, the microstructure consists primarily of large grains of the π phase with the L12 crystal structure, but second phase particles and pores are also present. The dislocation density in the π phase is low after homogenization. but increases substantially during compressive plastic deformation. In compression. Al67Ni8Ti25 has a yield strength of 355 MPa at room temperature and can exhibit substantial plasticity. The mechanism of compressive plastic deformation is a0〈110〉{111} slip. The a0〈110〉{111} dislocations are not dissociated by more than 2 nm, indicative of high {111} APB and SISF energies. Under the influence of a tensile stress, Al67Ni8Ti25is brittle and fails by transgranular cleavage. The brittle fracture behavior is consistent with ideas originally proposed by Rice and Thomson concerning an activation barrier for emission of dislocations from crack tips.</div>","PeriodicalId":6969,"journal":{"name":"Acta Metallurgica","volume":"37 10","pages":"Pages 2635-2643"},"PeriodicalIF":0.0,"publicationDate":"1989-10-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://sci-hub-pdf.com/10.1016/0001-6160(89)90296-4","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"83502558","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: 103

Temperature and orientation dependent plastic flow in Pt3Al 温度和取向对Pt3Al塑性流动的影响

Acta Metallurgica Pub Date : 1989-10-01 DOI: 10.1016/0001-6160(89)90309-X

F.E. Heredia, G. Tichy , D.P. Pope, V. Vitek

引用次数: 36

On the reciprocal lattice of the “premartensitic” R-phase in tini shape memory alloys 形状记忆合金中“预马氏体”r相的倒易晶格

Acta Metallurgica Pub Date : 1989-10-01 DOI: 10.1016/0001-6160(89)90315-5

S.K. Wu , C.M. Wayman

{"title":"On the reciprocal lattice of the “premartensitic” R-phase in tini shape memory alloys","authors":"S.K. Wu , C.M. Wayman","doi":"10.1016/0001-6160(89)90315-5","DOIUrl":"10.1016/0001-6160(89)90315-5","url":null,"abstract":"<div>The reciprocal lattice of a single R-phase variant formed in a Ti40NI51 shape memory alloy was investigated and it was found that <math><mtext>1</mtext><mtext>3</mtext></math><math><mtext>1</mtext><mtext>3</mtext></math><math><mtext>1</mtext><mtext>3</mtext></math> reflections arc situated on the elongated 〈111〉B2∗ direction corresponding to the rhombohedral expansion axis and that 0 <math><mtext>1</mtext><mtext>3</mtext></math><math><mtext>1</mtext><mtext>3</mtext></math> reflections lie on three 〈011〉B2∗ directions which are all perpendicular to the elongated 〈111〉B2∗ direction. There are four distinct R-phase reciprocal lattices corresponding to four distinct R-phasc variants. The four R-phase reciprocal lattices are related by twinning. Based on the R-phase reciprocal lattice, atomic shuffles in the R-phase transition are proposed. The high density of Ti11 Ni14 precipitates in the aged Ti49Ni51 alloy restrict the growth of R-phase variants, and therefore, superimposed reciprocal lattices of the distinct R-phase variants are often observed.</div>","PeriodicalId":6969,"journal":{"name":"Acta Metallurgica","volume":"37 10","pages":"Pages 2805-2813"},"PeriodicalIF":0.0,"publicationDate":"1989-10-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://sci-hub-pdf.com/10.1016/0001-6160(89)90315-5","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"119348005","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: 36

Correlations between short-range order parameters during short-range order reactions 短程阶数反应中短程阶数参数之间的相关性

Acta Metallurgica Pub Date : 1989-09-01 DOI: 10.1016/0001-6160(89)90042-4

U. Gahn, W. Pitsch

{"title":"Correlations between short-range order parameters during short-range order reactions","authors":"U. Gahn, W. Pitsch","doi":"10.1016/0001-6160(89)90042-4","DOIUrl":"10.1016/0001-6160(89)90042-4","url":null,"abstract":"<div>It is investigated by Monte Carlo simulations of short-range order reactions in an f.c.c. alloy A75B25 how the different short-range order parameters are correlated with each other. Thereby three alloys with an increasing number of energy parameters for the different coordination shells are studied at an annealing temperature, always 10% above the critical long-range ordering temperature. The values of the energy parameters are such that the long-range order below this temperature is always of Ll2-type (Cu3Au). The initial state of the crystal is always totally disordered. The correlations have been found to depend on the shell energies, on the atom occupations of those lattice sites, which directly influence the performance probability of the reaction step and on the crystallographic features of the operating diffusion mechanism. The latter point is investigated by employing besides the actual mechanism of vacancy interchanges with first neighbourhood atoms also e.g. the fictitious vacancy interchanges with atoms at random distances. The correlations, found by the Monte Carlo simulations, are quantitatively explained for the beginning of the reaction, where the atoms were randomly distributed onto the lattice sites.</div>","PeriodicalId":6969,"journal":{"name":"Acta Metallurgica","volume":"37 9","pages":"Pages 2455-2462"},"PeriodicalIF":0.0,"publicationDate":"1989-09-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://sci-hub-pdf.com/10.1016/0001-6160(89)90042-4","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"77246886","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: 12

Diffusion of silver in nanocrystalline copper between 303 and 373 K 银在纳米晶铜中在303 ~ 373 K间的扩散

Acta Metallurgica Pub Date : 1989-09-01 DOI: 10.1016/0001-6160(89)90046-1

S Schumacher, R Birringer, R Strauβ, H Gleiter

引用次数: 111

The relative stability of dislocations embedded in the β phase matrix and in martensite phases in copper based alloys 铜基合金中嵌入β相基体和马氏体相的位错的相对稳定性

Acta Metallurgica Pub Date : 1989-09-01 DOI: 10.1016/0001-6160(89)90029-1

F.C Lovey, A Hazarabedian , J.E Garces

{"title":"The relative stability of dislocations embedded in the β phase matrix and in martensite phases in copper based alloys","authors":"F.C Lovey, A Hazarabedian , J.E Garces","doi":"10.1016/0001-6160(89)90029-1","DOIUrl":"10.1016/0001-6160(89)90029-1","url":null,"abstract":"<div>Dislocations are observed in many shape memory alloys after thermal or stress cycling. The amount of dislocations (with Burgers vector <math><mtext>b</mtext><msub><mi></mi><mn>β</mn></msub><mtext> = a</mtext><msub><mi></mi><mn>0</mn></msub><mtext>〈010〉</mtext></math> and 〈1̄11〉 line direction in the β phase) increases with the number of cycles. The dislocations are accumulated in the sample and are incorporated in the corresponding growing phase. The relative energy of the dislocations when embedded in the parent phase or in one or another variant of martensite is evaluated in this work. The crystallographic changes of the dislocations provide a primary selection rule for those martensite variants in which the dislocations have the lowest energy. In order to proceed more quantitatively a full calculation of the dislocation energies has to be performed using the anisotropic theory. In this work these calculations have been made on the basis of measured elastic constants of the β and 2H phases of a Cu-Al-Ni alloy. It is found that a given dislocation could indeed have different energies depending whether it is embedded in the β phase or one or another oriented variant of martensite. In particular, those dislocations with Burgers vector lying on the basal plane of the 2H martensite show the lowest energy as compared to their self energy when embedded in other oriented variants (Burgers vector out of the basal plane) or in the β phase.</div>","PeriodicalId":6969,"journal":{"name":"Acta Metallurgica","volume":"37 9","pages":"Pages 2321-2327"},"PeriodicalIF":0.0,"publicationDate":"1989-09-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://sci-hub-pdf.com/10.1016/0001-6160(89)90029-1","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"78411430","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

Modelling solid-state diffusion bonding 模拟固态扩散键合

Acta Metallurgica Pub Date : 1989-09-01 DOI: 10.1016/0001-6160(89)90040-0

A. Hill , E.R. Wallach

引用次数: 192

A re-examination of the analysis of toughening in brittle-matrix composites 脆性基复合材料增韧分析的再检验

Acta Metallurgica Pub Date : 1989-09-01 DOI: 10.1016/0001-6160(89)90026-6

M.D Thouless

引用次数: 21