Heat Transfer at the Metal/Substrate Interface During Solidification of Pb-Sn Solder Alloys

2002 ◽  
Vol 11 (3) ◽  
pp. 265-273 ◽  
Author(s):  
K. Narayan Prabhu ◽  
S.T. Kumar ◽  
N. Venkataraman
Keyword(s):  
Heat Transfer ◽  
Metal Substrate ◽  
Solder Alloys ◽  
Substrate Interface

The relationship between thermal history and microstructure in spray-deposited tin-lead alloys

1991 ◽  
Vol 6 (7) ◽  
pp. 1433-1454 ◽  
Author(s):  
B.P. Bewlay ◽  
B. Cantor
Keyword(s):  
Heat Transfer ◽  
Grain Size ◽  
Thermal History ◽  
Numerical Models ◽  
Spray Deposition ◽  
Microstructural Analysis ◽  
Flow Rate Ratio ◽  
Flow Rates ◽  
Substrate Interface ◽  
Spray Deposit

Gas-atomized spray deposition involves the creation of a spray of droplets by a gas atomizer and the consolidation and solidification of these droplets on a substrate. The present paper describes an investigation of the fundamental characteristics of heat transfer and solidification during spray deposition. Spray deposition was used to manufacture Sn-15 and 38 wt. % Pb preforms using atomizer-substrate distances of 180 and 360 mm, gas flow rates of 2.5 and 3.4 g/s, and melt flow rates of 61 and 35 g/s. Analytical and numerical models were developed to predict the thermal history of the spray deposit for a range of deposit-substrate heat transfer coefficients. A deposit-substrate heat transfer coefficient of ∼104 W m−2 K−1 was determined by comparing measured and calculated spray-deposit thermal histories both during and after spray deposition. Microstructural analysis of transverse sections of the spray deposits revealed maximum values of spray-deposit density and cell/grain size at specific distances from the deposit-substrate interface. The distance between the density and cell/grain-size maxima and the deposit-substrate interface increased from 0.9 to 10 mm for Sn–15 wt. % Pb and from 2.6 to 11.3 mm for Sn–38 wt. % Pb as the atomizer-substrate distance was increased from 180 to 360 mm and the melt to gas mass flow rate ratio was decreased from 24 to 10. The origin of these microstructural features is described in terms of heat transfer during spray deposition.

scholarly journals Cavitation at filler metal/substrate interface during ultrasonic-assisted soldering. Part I: Cavitation characteristics

2018 ◽  
Vol 49 ◽  
pp. 249-259 ◽  
Author(s):  
Zhengwei Li ◽  
Zhiwu Xu ◽  
Lin Ma ◽  
Sheng Wang ◽  
Xuesong Liu ◽  
...  
Keyword(s):  
Filler Metal ◽  
Metal Substrate ◽  
Substrate Interface ◽  
Ultrasonic Assisted

Experimental Models for Assessment of Interfacial Heat Transfer in Dip Soldering

2009 ◽  
Vol 83-86 ◽  
pp. 1228-1235 ◽  
Author(s):  
Shankargoud Nyamannavar ◽  
K. Narayan Prabhu
Keyword(s):  
Heat Transfer ◽  
Heat Flux ◽  
Copper Substrate ◽  
Substrate Material ◽  
Experimental Models ◽  
Bulk Solder ◽  
Interfacial Region ◽  
Interfacial Heat Transfer ◽  
Test Probe ◽  
Substrate Interface

The success of a numerical simulation for solder solidification during soldering processes depends on an accurate knowledge of heat transfer phenomenon at the solder/substrate interface. Two experimental setups were designed to study the interfacial heat transfer at solder/substrate interface. In the first method, a cylindrical probe of substrate material was dipped in liquid solder and solder was allowed to solidify around the metal probe. In the second method the test probe was dipped in the bulk solder liquid of sufficiently large quantity and allowed to attain the surrounding solder liquid temperature. Temperature at the center of the probe was measured using thermocouple. Heat flux transients at the surface of the probe were estimated by lumped heat capacitance method. SEM study at the solder/substrate interfacial region for experiments of solidifying solder around the test probe revealed the existence of a clear gap with aluminum substrate. A conforming contact was obtained with copper substrate. The nature of heat flux transients was found to be different in two experiments.

scholarly journals Influence of Grain Refiners on the Wettability of Al2O3 Substrate by Aluminum Melt

2020 ◽  
Author(s):  
Jiawei Yang ◽  
Sarina Bao ◽  
Shahid Akhtar ◽  
Ping Shen ◽  
Yanjun Li
Keyword(s):  
Sessile Drop ◽  
Metal Substrate ◽  
Alumina Substrate ◽  
Ceramic Foam ◽  
Solidification Structure ◽  
Grain Refiner ◽  
Aluminum Melt ◽  
Substrate Interface ◽  
Master Alloys ◽  
Oxide Skin

AbstractIt is well known that grain refiner additions in aluminum melts significantly reduce the filtration efficiency of ceramic foam filters (CFF). However, the mechanism remains unclear. In this work, the influence of grain refiners on the wettability of alumina substrate by aluminum melt was studied by both conventional sessile drop and improved sessile drop methods at different temperatures and vacuums. Commercial purity aluminum (CP-Al) and grain refiner master alloys Al-3Ti-1B, Al-5Ti-1B, Al-3Ti-0.15C were used. It is found that master alloy melts wet alumina substrate better than CP-Al. Generally, a lower temperature or lower vacuum results in a higher contact angle. The roles of grain refiner particles in improving the wettability were studied by analyzing the solidification structure of post wetting-test droplets using SEM. Strong sedimentation of grain refiner particles at the metal-substrate interface was observed, which is attributed to the higher density of grain refiner particles compared to the Al melt. Meanwhile, a large fraction of grain refiner particles agglomerates at the oxide skin of the aluminum droplets, showing a strong adhesion between the particles and oxide skin. Such adhering of grain refiner particles is proposed to enhance the rupture of the original oxide skin of the droplets and slow down the reoxidation process at the surface layer. Both adherence of grain refiner particles to surface oxide skin and sedimentation of particles at the metal-substrate interface are responsible for the wetting improvement.

An Efficient Wavy Microchannel Heat Sink for Electronic Devices

2009 ◽  
Author(s):  
Y. Sui ◽  
C. J. Teo ◽  
P. S. Lee ◽  
Y. T. Chew ◽  
C. Shu
Keyword(s):  
Heat Transfer ◽  
Heat Sink ◽  
Heat Transfer Performance ◽  
Flow Direction ◽  
Electronic Devices ◽  
Metal Substrate ◽  
Chaotic Advection ◽  
Fluid Mixing ◽  
Transfer Performance ◽  
Dean Vortices

In this paper, we have designed a compact and efficient liquid-cooled heat sink for mini-sized electronic devices, particularly for very-large-scale integrated (VLSI) circuits. The heat sink can either be an integral part of the silicon (or metal) substrate, or a separate part attached onto the substrate. The heat sink consists of several wavy microchannels, with hydraulic diameter on the order of 100 μm, microfabricated on a silicon or metal substrate. The fluid flow and heat transfer performance of the heat sink are studied using numerical simulations in the steady laminar flow region and the dynamical system technique using Poincare´ sections is employed to analyze the fluid mixing. It is found that when the liquid coolant flows through the wavy microchannel, Dean vortices can develop. The quantity and location of the Dean vortices may change along the flow direction, which can lead to laminar chaos. The chaotic advection greatly enhances the fluid mixing, and thus the heat transfer performance of the present heat sink is much more superior than previous designs which employed straight microchannels. It is also found that the pressure drop penalty is much smaller that the heat transfer enhancement for the present heat sink. Furthermore, the relative wavy amplitude (wavy amplitude/wavelength) of the channels can be varied along the flow direction for various purposes, without compromising the compactness and efficiency of the heat sink. The relative waviness can be increased along the flow direction, which results in higher heat transfer coefficients and renders the temperature for the devices much more uniform. The relative waviness can also be designed to be higher in regions of high heat flux for hot spot mitigation purposes.

scholarly journals INTERMETALLIC COMPOUNDS FORMATION OF SOLDER ALLOYS ON Ni/Au SURFACE FINISH COPPER

2020 ◽  
Vol 26 (4) ◽  
pp. 184-187
Author(s):  
Ngoc Binh Duong
Keyword(s):  
Intermetallic Compounds ◽  
Melting Temperature ◽  
Surface Finish ◽  
Copper Substrate ◽  
Lead Free ◽  
Lead Free Solder ◽  
Solder Alloys ◽  
Soldering Temperature ◽  
Substrate Interface ◽  
Free Solder

Intermetallic compounds (IMCs) formation between lead-free solder alloys (Sn-9Zn and Sn-8Zn-3Bi) and Ni/Au surface finish copper substrate were studied. Reaction between the solder and the substrate was carried out at regular soldering temperature, approx. 50 °C above the melting temperature of the solder alloys. Results indicated that Au-Zn was the IMC formed at the interface and the Au layer which is electro-plated on the substrate has completely dissolved into the solder alloys. The amount of Au available at the interface is an important factor that influent the morphology of the IMC with thicker Au layer on the substrate resulted in thicker layer of IMC at the interface. Although Bi does not taken part in the composition of IMC, it influent the formation of IMC, the IMC formed in the Sn9Zn/substrate interface was Au5Zn3, meanwhile it was g2-AuZn3 in the Sn-8Zn-3Bi/substrate interface.

scholarly journals Heat transfer in volcano–ice interactions on Mars: synthesis of environments and implications for processes and landforms

2007 ◽  
Vol 45 ◽  
pp. 1-13 ◽  
Author(s):  
James W. Head ◽  
Lionel Wilson
Keyword(s):  
Heat Transfer ◽  
Ice Sheet ◽  
Volcanic Edifice ◽  
Lava Flows ◽  
Substrate Interface ◽  
Glacial Origin ◽  
Subglacial Volcanism

AbstractWe review new advances in volcano–ice interactions on Mars and focus additional attention on (1) recent analyses of the mechanisms of penetration of the cryosphere by dikes and sills; (2) documentation of the glacial origin of huge fan-shaped deposits on the northwest margins of the Tharis Montes and evidence for abundant volcano–ice interactions during the later Amazonian period of volcanic edifice construction and (3) the circumpolar Hesperian-aged Dorsa Argentea Formation, interpreted as an ice sheet and displaying marginal features (channels, lakes and eskers) indicative of significant melting and interior features interpreted to be due to volcano–ice interactions (e.g. subglacial volcanic edifices, pits, basins, channels and eskers). In this context, we describe and analyse several stages and types of volcano–ice interactions: (1) magmatic interactions with ice-rich parts of the cryosphere; (2) subglacial volcanism represented by intrusion under and into the ice and formation of dikes and moberg-like ridges, intrusion of sills at the glacier–volcano substrate interface and their evolution into subglacial lava flows, formation of subglacial edifices, marginal melting and channels; (3) synglacial (ice contact) volcanism represented by flows banking up against glacier margins, chilling and forming remnant ridges and (4) post-glacial volcanism and interactions with ice deposits.

Effect of Mold Surface Roughness on the Interfacial Heat Transfer Coefficient During Solidification of Solder Alloys

2012 ◽  
Vol 730-732 ◽  
pp. 751-756
Author(s):  
Antonio Carlos Pires Dias ◽  
Elisangela dos Santos Meza ◽  
F. Bertelli ◽  
Pedro R. Goulart ◽  
Noé Cheung ◽  
...  
Keyword(s):  
Heat Transfer ◽  
Surface Roughness ◽  
Heat Transfer Coefficient ◽  
Transfer Coefficient ◽  
Surface Finishing ◽  
Mold Surface ◽  
Interfacial Heat Transfer Coefficient ◽  
Low Carbon ◽  
Interfacial Heat Transfer ◽  
Solder Alloys

Solder joints are strongly dependent on how well the solder alloy can wet the substrate. One of the parameters which can be used to characterize the wettability of solder alloys on a substrate is the heat transfer coefficient at the interface alloy/substrate, hi. This study focus on the effect of the surface roughness of the substrate on the interfacial heat transfer coefficient during solidification of solder alloys. A comparative study is carried out with two lead-free solders alternatives and the traditional Sn-Pb solder (Sn 0.7wt%Cu, Sn 3.5 wt%Ag and Sn 38wt%Pb, respectively). These alloys were directionally solidified using a solidification apparatus having a water cooled bottom made of low carbon steel with two different surface finishing: machined and polished. The experimental thermal data collected by thermocouples positioned along the casting length were used as input information into an Inverse Heat Transfer Code implemented in this work in order to determine the hi variation in time. A power–law function given by (where a and m are constants which depend on the alloy composition, substrate and melt superheat and t is the time) which is based on both theoretical and experimental analyses is proposed. The transient hi profile has a typical drastic reduction from a high initial value due to the development of an air gap, followed by a recovery to an essentially constant value. The literature generally reports a decrease in hi with increasing surface roughness. However, in the present work an opposite behavior has been detected, which is explained based on contact interactions between alloy and substrate that are subjected to thermal contraction and thermal expansion during the soldering process, respectively.

Sign in / Sign up

Export Citation Format

Share Document