Ciência & Tecnologia dos Materiais最新文献_第8页

Influence of ageing treatment on the thermophysical characteristics and mechanical properties of forging wire Ni-rich NiTi alloy for superelastic applications 时效处理对超弹性锻丝富镍NiTi合金热物理特性和力学性能的影响

Ciência & Tecnologia dos Materiais Pub Date : 2017-01-01 Epub Date: 2017-07-10 DOI: 10.1016/j.ctmat.2016.07.013

P.F. Rodrigues , F.M.B. Fernandes , E.N. Texeira , S. Baptista , A.S. Paula , J.P. Oliveira

{"title":"Influence of ageing treatment on the thermophysical characteristics and mechanical properties of forging wire Ni-rich NiTi alloy for superelastic applications","authors":"P.F. Rodrigues , F.M.B. Fernandes , E.N. Texeira , S. Baptista , A.S. Paula , J.P. Oliveira","doi":"10.1016/j.ctmat.2016.07.013","DOIUrl":"10.1016/j.ctmat.2016.07.013","url":null,"abstract":"<div><p>NiTi alloys used for orthodontic applications need to show superelastic characteristics at room and oral temperatures. The ideal scenario is that where the material has a final austenitic phase transformation value below the room temperature. This study aims at understanding the influence of the ageing treatments in the austenitic structure at room temperature on a wire of a Ni-rich NiTi alloy produced by rotary forging by the evaluation of the phase transformation temperatures and mechanical behaviour in order to promote the superelastic behaviour at room temperature. The investigation was conducted using DSC (Differential Scanning Calorimetry) analysis and instrumented ultramicrohardness. The solubilisation at 950°C for 120min with water quenching showed a satisfactory amount of B2 phase at room temperature when compared to the sample after forging. After solubilisation, ageing treatment at 350°C for 30min gave a relatively higher hardness value and an Af temperature below the room temperature, ensuring the presence of austenitic phase at room and oral temperatures.</p></div>","PeriodicalId":10198,"journal":{"name":"Ciência & Tecnologia dos Materiais","volume":"29 1","pages":"Pages e23-e26"},"PeriodicalIF":0.0,"publicationDate":"2017-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://sci-hub-pdf.com/10.1016/j.ctmat.2016.07.013","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"84843793","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: 5

Residual stress field and distortions resulting from welding processes: numerical modelling using Sysweld 焊接过程中产生的残余应力场和变形:使用Sysweld的数值模拟

Ciência & Tecnologia dos Materiais Pub Date : 2017-01-01 Epub Date: 2017-07-10 DOI: 10.1016/j.ctmat.2016.07.015

Tiago R. Lima , Sérgio M.O. Tavares , Paulo M.S.T. de Castro

引用次数: 11

Shear cohesive law estimation of adhesive layers by digital image correlation 基于数字图像相关的黏结层剪切黏结规律估计

Ciência & Tecnologia dos Materiais Pub Date : 2017-01-01 Epub Date: 2017-07-10 DOI: 10.1016/j.ctmat.2016.05.002

A.C.C. Leitão, R.D.S.G. Campilho, J.C.S. Azevedo

{"title":"Shear cohesive law estimation of adhesive layers by digital image correlation","authors":"A.C.C. Leitão, R.D.S.G. Campilho, J.C.S. Azevedo","doi":"10.1016/j.ctmat.2016.05.002","DOIUrl":"10.1016/j.ctmat.2016.05.002","url":null,"abstract":"<div><p>Modern and competitive structures are sought to be strong, reliable and lightweight, which increased the industrial and research interest in adhesive bonding. With this joining technique, design can be oriented towards lighter structures. The large-scale application of a given joint technique supposes that reliable tools for design and failure prediction are available. Cohesive Zone Models (CZM) are a powerful tool, although the CZM laws of the adhesive bond in tension and shear are required as input in the models. This work evaluated the value of shear fracture toughness (<em>G</em><sub>IIC</sub>) and CZM laws of bonded joints. The experimental work consisted on the shear fracture characterization of the bond by a conventional and the <em>J</em>-integral techniques. Additionally, by the <em>J</em>-integral technique, the precise shape of the cohesive law is defined. For the <em>J</em>-integral, a digital image correlation method is used for the evaluation of the adhesive layer shear displacement at the crack tip (δ<sub>s</sub>) during the test, coupled to a Matlab<sup>®</sup> sub-routine for extraction of this parameter automatically. As output of this work, fracture data is provided in shear for the selected adhesive, allowing the subsequent strength prediction of bonded joints.</p></div>","PeriodicalId":10198,"journal":{"name":"Ciência & Tecnologia dos Materiais","volume":"29 1","pages":"Pages e119-e123"},"PeriodicalIF":0.0,"publicationDate":"2017-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://sci-hub-pdf.com/10.1016/j.ctmat.2016.05.002","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"80549473","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: 0

Use of advanced composite materials in strengthening axially loaded reinforced concrete columns 采用先进复合材料加固钢筋混凝土轴向受压柱

Ciência & Tecnologia dos Materiais Pub Date : 2017-01-01 Epub Date: 2017-07-10 DOI: 10.1016/j.ctmat.2016.07.008

M. Cheikh-Zouaoui , R. Benzaid , N. Chikh , H-A. Mesbah

引用次数: 0

Microreactors with embedded nanofibres manufactured by electrodynamic focusing 采用电动力聚焦技术制造嵌入纳米纤维的微反应器

Ciência & Tecnologia dos Materiais Pub Date : 2017-01-01 Epub Date: 2017-07-10 DOI: 10.1016/j.ctmat.2016.06.010

Ana Neilde R. da Silva , Demétrius S. Gomes , Rogerio Furlan , Maria Lúcia P. da Silva

引用次数: 2

Study of the viability of manufacturing ceramic moulds by additive manufacturing for rapid casting 快速铸造用增材制造陶瓷模具的可行性研究

Ciência & Tecnologia dos Materiais Pub Date : 2017-01-01 Epub Date: 2017-07-10 DOI: 10.1016/j.ctmat.2016.09.004

Edwin Ocaña Garzón , Jorge Lino Alves , Rui J. Neto

{"title":"Study of the viability of manufacturing ceramic moulds by additive manufacturing for rapid casting","authors":"Edwin Ocaña Garzón , Jorge Lino Alves , Rui J. Neto","doi":"10.1016/j.ctmat.2016.09.004","DOIUrl":"10.1016/j.ctmat.2016.09.004","url":null,"abstract":"<div><p>Additive manufacturing (AM) has been considered one of the best processes to manufacture components with complex geometries, many times impossible to achieve with traditional processes, such as moulds with conformal cooling. Binder Jetting (BJ) technology uses an ink-jet printing head that deposits an adhesive liquid, layer by layer, to bind a powder material that can be ceramic, metallic, or other, which allows manufacturing parts to be used in research and industry.</p><p>The aim of this work is to study the possibility of using BJ to produce plaster moulds for directly cast metallic parts at a lower cost than with metallic AM processes, using different types of infiltrates and post-processing parameters to improve the mechanical and thermal strength of moulds in order to be able to cast an aluminium alloy. The mechanical and thermal resistance of moulds with a thickness range of 2.5-4mm were analysed, as well as the surface roughness of metal samples, and compared with those obtained by traditional processes. Although all the moulds had good heat resistance during the casting, some did not have enough mechanical strength to withstand the metalostatic pressure, especially those with walls of 2.5 to 3.5mm.</p></div>","PeriodicalId":10198,"journal":{"name":"Ciência & Tecnologia dos Materiais","volume":"29 1","pages":"Pages e275-e280"},"PeriodicalIF":0.0,"publicationDate":"2017-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://sci-hub-pdf.com/10.1016/j.ctmat.2016.09.004","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"84291552","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: 8

Effect of the chemical milling process on the surface of titanium aluminide castings 化学铣削工艺对铝化钛铸件表面的影响

Ciência & Tecnologia dos Materiais Pub Date : 2017-01-01 Epub Date: 2017-07-10 DOI: 10.1016/j.ctmat.2016.08.004

Rui Neto, Teresa Duarte, Jorge Lino Alves, Francisco Torres, João Pinto

{"title":"Effect of the chemical milling process on the surface of titanium aluminide castings","authors":"Rui Neto, Teresa Duarte, Jorge Lino Alves, Francisco Torres, João Pinto","doi":"10.1016/j.ctmat.2016.08.004","DOIUrl":"10.1016/j.ctmat.2016.08.004","url":null,"abstract":"<div><p>Most of titanium aluminide (TiAl) castings used in the automotive and aeronautical industries, such as turbines, are high added- value parts with complex geometries. Due to high reactivity of TiAl cast into ceramic moulds, most of the castings require post- processing in order to remove a brittle surface layer named alpha case. Furthermore, the complex geometry and thin walls of this type of components makes difficult to cast net shape parts; so, near-net shape components with machining allowance are often produced to improve mould filling (better fluidity). To solve this technological limitation, the chemical milling process is used to eliminate this layer and the machining allowance. In bibliography there are only a few systematic studies about the influence of chemical milling in TiAl surface castings. So, this experimental work seeks to contribute to understand the influence of this finishing process on the TiAl castings surface quality (dimensional accuracy, roughness and microhardness) and intends to establish which of the two chemical solutions tested is better for chemical milling of TiAl castings.</p></div>","PeriodicalId":10198,"journal":{"name":"Ciência & Tecnologia dos Materiais","volume":"29 1","pages":"Pages e40-e45"},"PeriodicalIF":0.0,"publicationDate":"2017-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://sci-hub-pdf.com/10.1016/j.ctmat.2016.08.004","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"84288698","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: 1

Local Surface Plasmon Resonance of metallic nanoparticles embedded in amorphous silicon 嵌入非晶硅中的金属纳米颗粒的局部表面等离子体共振

Ciência & Tecnologia dos Materiais Pub Date : 2017-01-01 Epub Date: 2017-07-10 DOI: 10.1016/j.ctmat.2016.06.011

A. Fantoni , M. Fernandes , Y. Vigranenko , M. Vieira

引用次数: 1

Urbcork – Urban furniture with application of high density cork 城市软木-应用高密度软木的城市家具

Ciência & Tecnologia dos Materiais Pub Date : 2017-01-01 Epub Date: 2017-07-10 DOI: 10.1016/j.ctmat.2016.06.005

Mariana Alves , Lígia Lopes , Jorge Lino Alves , Francisco Xavier de Carvalho

{"title":"Urbcork – Urban furniture with application of high density cork","authors":"Mariana Alves , Lígia Lopes , Jorge Lino Alves , Francisco Xavier de Carvalho","doi":"10.1016/j.ctmat.2016.06.005","DOIUrl":"10.1016/j.ctmat.2016.06.005","url":null,"abstract":"<div><p>Urbcork is an urban furniture line developed at the Faculty of Engineering of the University of Porto (FEUP) for the collection produced by Leets Urban Design. It can be highlighted for its sustainable properties and inclusive design concerns.</p><p>Urban furniture is a product to be used by a large number of people in a public space. It has a high level of wear and ageing due to the intensive use, solar exposure and weather conditions.</p><p>During the project development there was a conceptual idea about using cork as the main material for the seat and the back. The opportunity of developing a prototype brought the question about how to keep cork properties after a long exposure on exterior.</p><p>The main line of investigation was about how to protect cork keeping its natural appearance and extending its properties and conservation over time. Laboratory tests held at CTCOR and FEUP were conducted in order to understand the behaviour of cork on extreme conditions. The results are not yet successful, but with more tests, the product can be well accepted in the international market.</p></div>","PeriodicalId":10198,"journal":{"name":"Ciência & Tecnologia dos Materiais","volume":"29 1","pages":"Pages e270-e274"},"PeriodicalIF":0.0,"publicationDate":"2017-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://sci-hub-pdf.com/10.1016/j.ctmat.2016.06.005","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"87942998","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: 1

Shear fracture toughness and cohesive laws of adhesively-bonded joints 粘接接头剪切断裂韧性及粘接规律

Ciência & Tecnologia dos Materiais Pub Date : 2017-01-01 Epub Date: 2017-07-10 DOI: 10.1016/j.ctmat.2016.05.003

J.C.S. Azevedo, R.D.S.G. Campilho, F.J.G. Silva

{"title":"Shear fracture toughness and cohesive laws of adhesively-bonded joints","authors":"J.C.S. Azevedo, R.D.S.G. Campilho, F.J.G. Silva","doi":"10.1016/j.ctmat.2016.05.003","DOIUrl":"10.1016/j.ctmat.2016.05.003","url":null,"abstract":"<div><p>Adhesive bonding is a viable technique to reduce weight and complexity in structures. Additionally, this joining technique is also a common repair method for metal and composite structures. However, a generalized lack of confidence in the fatigue and long-term behaviour of bonded joints hinder their wider application. Suitable strength prediction techniques must be available for the application of adhesive bonding, and these can be based on mechanics of materials, conventional fracture mechanics or damage mechanics. These two last methodologies require the knowledge of the fracture toughness (<em>G</em><sub><em>C</em></sub>) of materials. Being damage mechanics-based, Cohesive Zone Modelling (CZM) analyses coupled with Finite Elements (FE) are under investigation. In this work, CZM laws were estimated in shear for a brittle adhesive (Araldite<sup>®</sup> AV138) and high-strength aluminium adherends, considering the End-Notched Flexure (ENF) test geometry. The CZM laws were obtained by an inverse methodology based on curve fitting, which made possible the precise estimation of the adhesive joints’ behaviour. It was concluded that a unique set of shear fracture toughness (<em>G</em><sub>IIC</sub>) and shear cohesive strength (<em>t</em><sub>s</sub><sup>0</sup>) exists for each specimen that accurately reproduces the adhesive layer behaviour. With this information, the accurate strength prediction of adhesive joints in shear is made possible by CZM.</p></div>","PeriodicalId":10198,"journal":{"name":"Ciência & Tecnologia dos Materiais","volume":"29 1","pages":"Pages e124-e129"},"PeriodicalIF":0.0,"publicationDate":"2017-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://sci-hub-pdf.com/10.1016/j.ctmat.2016.05.003","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"85869199","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: 1