Kamalesh Kumar, Ram Subramanian and Karen Strandholm
This study examines the scanning/strategy relationship in the context‐specific setting of the health care industry. It extends the current research on the strategy/scanning…
Abstract
This study examines the scanning/strategy relationship in the context‐specific setting of the health care industry. It extends the current research on the strategy/scanning relationship to include performance. Results confirm the moderating role played by environmental scanning activities in the strategy/performing relationship, thus providing further evidence for the contingency relationship among the environment, the organization's internal processes, and performance.
To determine the role of microstructure in the creep and thermomechanical fatigue (TMF) properties of solder joints made with eutectic Sn‐Ag solder, and Sn‐Ag solder with Cu…
Abstract
Purpose
To determine the role of microstructure in the creep and thermomechanical fatigue (TMF) properties of solder joints made with eutectic Sn‐Ag solder, and Sn‐Ag solder with Cu and/or Ni additions.
Design/methodology/approach
Quaternary alloys containing small amounts of Cu and Ni exhibit better high temperature creep resistance and also better resistance to damage under TMF cycles with a longer dwell time at the high temperature extreme, than eutectic Sn‐Ag, and Sn‐Ag‐Cu ternary alloy solder joints. Microstructural evaluation was conducted to investigate the effects of Ni additions to Sn‐Ag‐based solder joints.
Findings
Microstructural studies of the quaternary solder alloys revealed the presence of small ternary Cu‐Ni‐Sn intermetallic compound particles at Sn‐Sn grain boundaries. These precipitates can retard the grain boundary sliding that will occur during TMF with longer dwell times at the high temperature extreme, and during high temperature creep.
Originality/value
The findings of this paper will help to provide an understanding of the effects of alloying elements on Sn‐Ag based solder joints.
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Jorge F. B. Lengler, Carlos M. P. Sousa and Catarina Marques
Despite some attempts to integrate the market orientation construct into the international marketing area, most conceptual and empirical studies have been conducted in the context…
Abstract
Despite some attempts to integrate the market orientation construct into the international marketing area, most conceptual and empirical studies have been conducted in the context of domestic operations. To address this gap we examine whether competitive intensity moderates the relationships among the components of market orientation and export performance. Data was used from 197 Brazilian export companies. Results suggest that interfunctional coordination enhances customer and competitor orientation. Moreover, customer orientation has no direct effect on export performance, while competitor orientation has a positive effect on firm’s international performance. Findings also indicate that competitive intensity moderates all the relationships tested in the model.
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Saravanan C., Subramanian K., Anandakrishnan V. and Sathish S.
Aluminium is the most preferred material in engineering structural components because of its excellent properties. Furthermore, the properties of aluminium may be enhanced through…
Abstract
Purpose
Aluminium is the most preferred material in engineering structural components because of its excellent properties. Furthermore, the properties of aluminium may be enhanced through metal matrix composites and an in-depth investigation on the evolved properties is needed in view of metallurgical, mechanical and tribological aspects. The purpose of this study is to explore the effect of TiC addition on the tribological behavior of aluminium composites.
Design/methodology/approach
Aluminium metal matrix composites at different weight percentage of titanium carbide were produced through powder metallurgy. Produced composites were subjected to sliding wear test under dry condition through Taguchi’s L9 orthogonal design.
Findings
Optimal process condition to achieve the minimum wear rate was identified though the main effect plot. Sliding velocity was identified as the most dominating factor in the wear resistance.
Practical implications
The production of components with improved properties is promoted efficiently and economically by synthesizing the composite via powder metallurgy.
Originality/value
Though the investigations on the wear behavior of aluminium composites are analyzed, reinforcement types and the mode of fabrication have their significance in the metallurgical and mechanical properties. Thus, the produced component needs an in-detail study on the property evolution.
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To understand the roles of service‐related parameters, such as imposed cyclic strain amplitude and cyclic strain rate, on the stress relaxation behaviour of eutectic Sn‐Ag solder…
Abstract
Purpose
To understand the roles of service‐related parameters, such as imposed cyclic strain amplitude and cyclic strain rate, on the stress relaxation behaviour of eutectic Sn‐Ag solder joints.
Design/methodology/approach
Cyclic shear straining with associated stress relaxation at the shear strain extremes imposed was carried out on pre‐strained eutectic Sn‐Ag solder joints with various cyclic shear straining conditions. Results from such experiments were compared with previously reported findings from monotonic shear straining and stress relaxation tests.
Findings
At higher testing temperatures with a larger cyclic strain amplitude, stress states realized at the subsequent cycle are comparable with, or even gradually increase on, those experienced at the previous cycle, especially after few cycles. The maximum shear stress obtained at each cycle and residual stress during stress relaxation are strongly affected by cyclic strain rate. Stress relaxation during subsequent cycles of straining was found to be strongly dependent on the test temperature, and the imposed cyclic strain amplitude and cyclic strain rate.
Originality/value
In this paper, the experiments were carried out on eutectic Sn‐Ag solder joints with about a 100 μm joint thickness, which are, therefore, representative of those used in microelectronics. Also, there is no systematic study reporting the effects of cyclic straining conditions on the stress relaxation behaviour of eutectic Sn‐Ag solder for this joint configuration in the published literature.
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H. Rhee, K.N. Subramanian, A. Lee and J.G. Lee
Deformation studies on eutectic Sn‐Ag solder (Sn‐3.5Ag in wt percent) joints were carried out at a range of temperatures using a rheometric solids analyzer (RSA‐III). Various…
Abstract
Deformation studies on eutectic Sn‐Ag solder (Sn‐3.5Ag in wt percent) joints were carried out at a range of temperatures using a rheometric solids analyzer (RSA‐III). Various performance parameters were evaluated with this equipment by subjecting geometrically realistic solder joints to shear loading at various temperatures (25, 75, 100, 125, and 150°C) with a nominal joint thickness of ∼100 μm and 1×1 mm solder joint area. Mechanical properties such as shear stress versus simple shear‐strain relationships, peak shear stress as a function of rate of simple shear‐strain and testing temperature, and creep parameters were evaluated to gain a better understanding of the parameters contributing to thermomechanical fatigue.
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F. Guo, J. Lee and K.N. Subramanian
In an attempt to improve service life of lead‐free Sn‐based electronic solder joints, compatible reinforcements were introduced by in‐situ and mechanical mixing methods. The…
Abstract
In an attempt to improve service life of lead‐free Sn‐based electronic solder joints, compatible reinforcements were introduced by in‐situ and mechanical mixing methods. The reinforcements affect the steady‐state creep rate and the strain for the onset of tertiary creep of the solder joints. However, neither of these parameters, when considered alone, can be used for evaluating the reliability of solder joints. The Larson‐Miller parameter, and a new parameter proposed in the paper, can incorporate test parameters to arrive at a reliability prediction methodology. The role of these reinforcements in homogenising creep strain within the joint is analysed. The observed creep behaviour of these composite solders is discussed on the basis of interfacial bonding strength between the reinforcement and the solder matrix.
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J.G. Lee, F. Guo, K.N. Subramanian and J.P. Lucas
The influence of the thermal reflow profile on the formation and resultant morphology of the intermetallic layer that developed at the Ni particle reinforcements within an…
Abstract
The influence of the thermal reflow profile on the formation and resultant morphology of the intermetallic layer that developed at the Ni particle reinforcements within an eutectic Sn‐Ag composite solder matrix was investigated. The composite solder was fabricated by mechanically dispersing 15 vol% Ni particles into eutectic Sn‐3.5Ag solder paste. Two distinct intermetallic compound (IMC) morphological microstructures were observed around the Ni reinforcements. IMC morphological microstructure apparently varied depending on the amount of heat input and differences in heating rates used in the reflow profile. A “sunflower” IMC morphology was typically noted when the total amount of heat input was small. However, with sufficient heat input, a faceted “blocky” IMC morphology was consistently achieved. Multiple‐reflow thermal profiling experiments were conducted to measure and compare the amount of heat input necessary to change the sunflower IMC morphology around Ni particle reinforcements to the blocky morphology.
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F. Guo, S. Choi, J.P. Lucas and K.N. Subramanian
Composite solders were prepared by mechanically dispersing 15v% of Cu or Ag particles into the eutectic Sn‐3.5Ag solder. The average sizes for the nominally spherical Cu and Ag…
Abstract
Composite solders were prepared by mechanically dispersing 15v% of Cu or Ag particles into the eutectic Sn‐3.5Ag solder. The average sizes for the nominally spherical Cu and Ag particles were 6 and 4 microns, respectively. Two different processing methods were used to prepare the composite solders: blending the powdered particles with solder paste, and adding particles to the molten solder at 2808C. The composite solders were characterised by studying the morphology, size and distribution of the reinforcing phase. Particular interest and emphasis are given towards the modifications of the reinforcements during the reflow process. Microstructural features and chemical analysis of the composite solders were studied using optical and scanning electron microscopy (SEM), and energy dispersive x‐ray (EDX) analysis. The effect of reflow and isothermal ageing on the microstructure as well as the morphological changes in the interfacial IM layer of the composite solders were extensively analysed. A mechanism for IM layer growth is proposed for solid state isothermal ageing.