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Article
Publication date: 1 December 2000

H.D. Merchant, J.T. Wang, L.A. Giannuzzi and Y.L. Liu

In this paper, we consider intrinsic properties of copper electrodeposited as plateup on polyimide substrate, thermal response of electrodeposited copper and fatigue performance…

2267

Abstract

In this paper, we consider intrinsic properties of copper electrodeposited as plateup on polyimide substrate, thermal response of electrodeposited copper and fatigue performance of copper and copper/polyimide construction. The critical material characteristics examined are grain morphology and structure, crystallographic texture, microhardness, uniaxial strength and ductility and isothermal cyclic fatigue life. Given optimum processing conditions, copper plateup in flexible circuits displays fine grain structure, high ductility, adequate thermal stability, freedom from thermal embrittlement and excellent fatigue endurance over a wide range of strain amplitudes.

Details

Circuit World, vol. 26 no. 4
Type: Research Article
ISSN: 0305-6120

Keywords

Article
Publication date: 1 April 1998

W. Kinzy Jones, Yanqing Liu, Milind Shah and Robert Clarke

The mechanical properties of eight solder alloys from the Pb‐Sn‐In‐Ag alloy systems were determined over the temperature range ‐200°C to 100°C, using uniaxial tensile tests…

1935

Abstract

The mechanical properties of eight solder alloys from the Pb‐Sn‐In‐Ag alloy systems were determined over the temperature range ‐200°C to 100°C, using uniaxial tensile tests, dynamic mechanical analysis (DMA), acoustic pulse methods and dilatometry. In general, the strength and elastic modulus of the alloys studied was inversely dependent on temperature. PbSn, PbIn and SnIn alloys were observed to turn superplastic with elongations over 100 per cent at temperatures of 50°C or above. The Pb‐based and In‐Sn eutectic solders possessed superplasticity at temperatures greater than 50°C. From these results, deformation and fracture processes are reviewed, and the appropriate fracture mechanism is proposed.

Details

Soldering & Surface Mount Technology, vol. 10 no. 1
Type: Research Article
ISSN: 0954-0911

Keywords

Article
Publication date: 24 May 2013

Ch. Alk. Apostolopoulos and Vassilios Kappatos

The corrosion of reinforcing steel bars reduces significantly the life and durability of concrete structures. This critical concern causes great losses to the economy and…

Abstract

Purpose

The corrosion of reinforcing steel bars reduces significantly the life and durability of concrete structures. This critical concern causes great losses to the economy and industry. The purpose of this paper is to estimate the effects of corrosion on the tensile mechanical properties of embedded steel bars B500c in concrete.

Design/methodology/approach

The concept is based on the curve fitting modelling, as well the mathematical correlation of the tensile mechanical properties between corroded bare and corroded embedded steel bars. In order to achieve this, extensive experiments were carried out on both bare (Ø8, 10, 12, 16 and 18 mm) and embedded (Ø8 mm) steel bars B500c, which were subjected to artificially accelerated corrosive conditions in a chloride‐rich atmosphere for several exposure times.

Findings

The research results show that the estimation method is available and effective in simulating the tensile mechanical behaviour of corroded reinforcing steel bars B500c.

Originality/value

As far as is known, this is the first time that an advanced data processing technique has been employed to try to find the mathematical correlation of the existing corrosion damage on the residual tensile properties between bare and embedded steel bars. It is argued that these models can be developed in order to reduce the need for expensive experimental investigation in materials.

Details

International Journal of Structural Integrity, vol. 4 no. 2
Type: Research Article
ISSN: 1757-9864

Keywords

Article
Publication date: 30 October 2018

Benjamin Himmel, Dominik Rumschoettel and Wolfram Volk

Directly printing molten metal droplets on a build platform to create full dense metal parts is a promising additive manufacturing process. This study aims of to analyse the…

Abstract

Purpose

Directly printing molten metal droplets on a build platform to create full dense metal parts is a promising additive manufacturing process. This study aims of to analyse the effects of the thermal conditions on the resulting tensile properties of parts made from aluminium 4047A built in droplet-based metal printing.

Design/methodology/approach

A drop-on-demand print head with pneumatic actuation is used to eject droplets on a nickel sheet mounted on the heated build platform. Tensile specimens are machined from cuboid blocks built by successive droplet deposition and tested in a universal testing machine. The ultimate tensile strength, uniform elongation and yield strength are evaluated and presented. Micro-sections are taken from the printed blocks to examine the internal pores and the metal’s microstructure.

Findings

With an increase in the interface temperature the uniform elongation increases from 0.5 to 12%, while the yield strength decreases from 130 to 90 MPa. The ultimate tensile strength increases from 130 MPa to a maximum of 190 MPa at an interface temperature of 530º C and slightly falls for higher interface temperatures. Those values are in the same range as conventionally casted parts of the same alloy. The authors’ hypothesis is that the main effect responsible for the mechanical properties is the wetting of solid material by the liquid droplet and not remelting, as has been reported in literature.

Originality/value

To the best of the authors’ knowledge, this is the first time that mechanical properties of aluminium 4047A built by a droplet-based additive manufacturing process are published for different interface temperatures. It is also the first time that the main effect on mechanical properties is attributed to wetting instead of remelting.

Details

Rapid Prototyping Journal, vol. 25 no. 2
Type: Research Article
ISSN: 1355-2546

Keywords

Article
Publication date: 8 April 2022

Fuminobu Ozaki and Takumi Umemura

In this study, engineering stress-strain relationships considering an effect of strain rate on steel materials at elevated temperatures were formulated and a simplified analytical…

Abstract

Purpose

In this study, engineering stress-strain relationships considering an effect of strain rate on steel materials at elevated temperatures were formulated and a simplified analytical model using a two-dimensional beam element to analytically examine the effect of strain rate on the load-bearing capacity and collapse temperature was proposed.

Design/methodology/approach

The stress-strain relationships taking into account temperature, strain, and strain rate were established based on the past coupon test results with strain rate as the test parameter. Furthermore, an elasto-plastic analysis using a two-dimensional beam element, which considered the effect on strain rate, was conducted for both transient- and steady-state conditions.

Findings

The analytical results agreed relatively well with the test results, which used small steel beam specimens with a rectangular cross-section under various heating rates (transient-state condition) and deformation rates (steady-state condition). It was found that the bending strength and collapse temperature obtained from the parametric analyses agreed relatively well with those evaluated using the effective strength obtained from the coupon tests with strain equal to 0.01 or 0.02 under the fast strain rates.

Originality/value

The effect of stress degradation, including the stress-strain relationships at elevated temperature, was mitigated by considering the effect of strain rate on the analytical model. This is an important point to consider when considering the effect of strain rate on steel structural analysis at elevated temperatures to maintain analytical stability unaccompanied by the stress degradation.

Article
Publication date: 1 September 1950

B. Salmon

First type isostatic lines: tangents at every point to the maximum principal deformation and stress, in algebraic values.1.0 WHEN an engineer sets out to calculate the shape and…

Abstract

First type isostatic lines: tangents at every point to the maximum principal deformation and stress, in algebraic values.

1.0 WHEN an engineer sets out to calculate the shape and dimensions of parts of machinery he becomes rapidly aware of his ignorance. Mechanical parts have such singular shapes and dimensions and are supported under such conditions that no practical method of calculation will satisfy them.

Details

Aircraft Engineering and Aerospace Technology, vol. 22 no. 9
Type: Research Article
ISSN: 0002-2667

Article
Publication date: 22 September 2022

Srinivasan Raghavan, Jan Dzugan, Sylwia Rzepa, Pavel Podany, Norman Soh, Lim Jia Hao and Niaz Khan

This study aims to investigate the effect of the wall thickness, deposition orientation and two different post-processing methods on the local mechanical properties and…

Abstract

Purpose

This study aims to investigate the effect of the wall thickness, deposition orientation and two different post-processing methods on the local mechanical properties and microstructure of additively manufactured parts made of maraging steel. In order to examine the local properties of the build, miniaturized testing specimens were employed. Before application of small-sized specimens, their performance was verified.

Design/methodology/approach

The investigation was composed of two stages. As first, the part thickness, specimen size and orientation were studied on a laser-powder bed fusion (L-PBF) platform with deposited walls of various thicknesses made of maraging steel. Subsequently, the influence of different heat-treatment methods was investigated on the final product, i.e. impellers. The miniaturized and standard tensile tests were performed to investigate the local mechanical properties. The porosity, microstructures and fracture surfaces were analysed by X-ray-computed tomography, X-ray diffraction and scanning electron microscopy with electron backscatter diffraction.

Findings

The results revealed good agreement between the values provided by miniaturized and standard specimens. The thinnest parts produced had the largest pores and the highest scatter of elongation values. In these cases, also the sub-contour porosity was observed. Part thickness affected pores’ size and results repeatability but not total porosity. The two-step heat-treatment (solutionizing and age-hardening) exhibited the highest yield and ultimate tensile strength.

Practical implications

The microstructure and local mechanical properties were studied on L-PBF platform with deposited walls of various thicknesses. Subsequently, a detailed analysis was conducted on real components (impellers) made of maraging steel, commonly used in tooling, automotive and aerospace industries.

Originality/value

The broadly understood quality of manufactured parts is crucial for their reliable and long-lasting operation. The findings presented in the manuscript allow the readers better understanding of the connection between deposition parameters, post-processing, microstructure and mechanical performance of additive manufacturing-processed parts.

Article
Publication date: 1 February 1990

J.S. Hwang and R.M. Vargas

Solder joint long‐term reliability is an ultimate requirement for electronics packaging. Solder joint failure, however, can involve complex mechanisms. One of many basic failure…

Abstract

Solder joint long‐term reliability is an ultimate requirement for electronics packaging. Solder joint failure, however, can involve complex mechanisms. One of many basic failure processes in metals/alloys is the creep phenomenon. Creep is defined as a time‐dependent deformation when a material is subjected to a stress for a prolonged period of time. This time‐dependent deformation can theoretically occur at any temperature above absolute zero. However, creep‐dominant failure normally occurs under high temperature in relation to the melting point of the material. Common solders are low temperature alloys with melting point or liquidus/solidus temperature in the range of 120–320°C. Therefore a detectable creep process under low level of mechanical load is expected even at ambient temperature. This paper presents the preliminary data on the comparative creep rate of twenty‐two common solder alloys and attempts to correlate the creep rate to the tensile strength, modulus, melting point and microstructure of alloys. The alloys under study include Sn/Pb, Sn/Pb/Ag, Sn/Ag, Sn/Sb, Sn/Pb/Bi, Sn/Pb/Sb, Sn/Bi, Sn/In, and Pb/In systems. This paper also discusses the proposed mechanisms for solder creep phenomena. It is hoped that the data in this work will provide additional fundamental mechanical properties of various solder alloys, which are much needed to facilitate the design of reliable solder joint structure.

Details

Soldering & Surface Mount Technology, vol. 2 no. 2
Type: Research Article
ISSN: 0954-0911

Article
Publication date: 11 June 2018

Halyna Krechkovska, Oleksandra Student, Grzegorz Lesiuk and José Correia

The purpose of this paper is to assess the technical state of old and repair steels of Shukhov’s tower elements after operation during ~ 110 and 70 years of the water tower in…

Abstract

Purpose

The purpose of this paper is to assess the technical state of old and repair steels of Shukhov’s tower elements after operation during ~ 110 and 70 years of the water tower in Nikolaev, basing on their mechanical tests, metallography and fractography investigations.

Design/methodology/approach

For their certification, the fractographic and structural features and mechanical properties (hardness, strength, plasticity and impact toughness) were analyzed. Both the steels under consideration were characterized by low values of hardness and brittle fracture resistance. The mechanical characteristics of the old steel are lower compared with the repair one. It cannot be only explained by the quality of metal rolling. Moreover, the plasticity characteristics of both steels, defined in synthetic acid rain environment, are lower than in the air. Using fractography investigation, the operational damages in the bulk metal in the form of the elements of cleavage fracture in the central part of the fracture surfaces of specimens tested at the hydrogenation condition by synthetic acid rain environment were revealed.

Findings

The results of this study suggested a degradation of steels’ characteristics caused by the development of scattering damages during their operation. Higher relative elongation of the old steel at lower hardness and impact toughness were also evidenced in that. The metallography and fractography investigations also supported this finding.

Originality/value

This original study aimed at characterizing the microstructural and mechanical degradation of mild steels that was collected from Shukhov’s tower structural elements.

Details

International Journal of Structural Integrity, vol. 9 no. 3
Type: Research Article
ISSN: 1757-9864

Keywords

Article
Publication date: 1 March 1984

Dear Sir, The reply (in Vol. 10, No. 2, 1984) from Messrs P. M. Smith and R. Rolff to my correspondence regarding Mr Smith's paper ‘A New Method of Testing the Ductility of…

Abstract

Dear Sir, The reply (in Vol. 10, No. 2, 1984) from Messrs P. M. Smith and R. Rolff to my correspondence regarding Mr Smith's paper ‘A New Method of Testing the Ductility of Electroplated Foil’ in your February 1983 issue cannot stand without a further retort from me. Nothing that was advanced in their reply changes the points made in my initial letter.

Details

Circuit World, vol. 10 no. 4
Type: Research Article
ISSN: 0305-6120

1 – 10 of 852