Effect of Sn Component Surface Finish on 92.5Pb-5Sn-2.5Ag

2014 ◽  
Vol 2014 (HITEC) ◽  
pp. 000364-000371
Author(s):  
Harry Schoeller ◽  
Martin Anselm ◽  
Imran Khan ◽  
Eric Cotts
Keyword(s):  
High Temperature ◽  
Mechanical Behavior ◽  
Surface Finish ◽  
Solder Joints ◽  
Mechanical Performance ◽  
Mechanical Tests ◽  
Fatigue Tests ◽  
Scanning Calorimetry ◽  
Microstructure Evaluation ◽  
Final Composition

This work investigates the effect of Sn component surface finish on the melting temperature, microstructure, and mechanical behavior of 92.5Pb-5Sn-2.5Ag. 92.5Pb-5Sn-2.5Ag was doped with up to 7% Sn to simulate the final composition of a joint after reflow with a component having Sn surface finish. Differential Scanning Calorimetry (DSC) was used to measure the change in matrix liquidus temperature with increasing Sn concentration. Microstructure evaluation and mechanical tests were carried out on 20 mil solder spheres reflowed on high temperature polyimide test coupons. Solder joints of each composition were cross-sectioned to examine the microstructure. The area fraction of β-Sn and Ag3Sn was quantified for each composition using image analysis software. Shear and isothermal fatigue tests of individual solder joints with varying Sn concentrations were conducted at room temperature. Joints were also sheared at 200°C after aging for 1024hrs at 200°C to simulate a downhole environment. The failed interfaces were examined to determine the mode of failure. Beyond providing guidance for surface finish selection, this work examines the microstructure and mechanical behavior of 92.5Pb-5Sn-2.5Ag as a function of Sn concentration and temperature. An understanding of the microstructure-mechanical performance relationship will aid in the development of new alloys for high temperature applications.

Adhesives for increasing the bonding strength of in situ manufactured metal-composite joints

2020 ◽  
pp. 095440702096575
Author(s):  
Robert Thomas ◽  
Fabian Fischer ◽  
Maik Gude
Keyword(s):  
Bonding Strength ◽  
Elevated Temperatures ◽  
Mechanical Performance ◽  
Storage Conditions ◽  
Mechanical Tests ◽  
Metal Composite ◽  
Scanning Calorimetry ◽  
Lap Shear ◽  
Glass Fibre Reinforced ◽  
Metallic Parts

In this present work, the potential of metallic parts, locally reinforced with a continuous glass fibre reinforced thermoset material, pre-impregnated with an epoxy matrix (prepreg), was evaluated by differential scanning calorimetry (DSC), single-lap shear tests and 3-point bending tests of a metal-composite hybrid hat profile. This technology is evaluated regarding an automotive use case, the DSC experiments in combination with moulding trials have proven curing times below 30 s for a moulding temperature of 180°C. A bonding strength of 13.5 MPa was characterized for a co-cured fibre-reinforced plastic (frp) onto a metallic joining partner. By additionally introducing an epoxy glue film as a bonding agent, which is co-cured together with the frp, the bonding strength can be increased significantly up to 25.4 MPa at the expense of the curing time. The mechanical tests on the hybrid hat profile have shown an increase of energy absorption compared with non-reinforced hat profiles. Here, also an additional glue film extends the performance regarding a co-cured plastic reinforcement without glue film. The influence of the storage conditions of the uncured prepreg materials on the mechanical performance was evaluated by a simulated physical ageing at elevated temperatures, followed by a mechanical characterization of the bonding strength and part performance. Also the effect of different testing temperatures and testing velocities on the capability of the metal-composite hybrid part is illustrated.

Study of Processing and Properties of a few Hemp Linter Fiber Reinforced Polylactic Acids Composite Materials

2011 ◽  
Vol 332-334 ◽  
pp. 1785-1789
Author(s):  
Jia Shuang Luan ◽  
Mei Zhang ◽  
Fu Gui Zhou ◽  
Yang Wang ◽  
Gang Ma ◽  
...  
Keyword(s):  
Thermogravimetric Analysis ◽  
Mechanical Performance ◽  
Average Molecular Weight ◽  
Degradation Process ◽  
Mechanical Tests ◽  
Scanning Calorimetry ◽  
Hemp Fiber ◽  
Batch Mixing ◽  
Sample Count ◽  
Poly Ethylene

Composites of poly(L-lactide) (PLA) with hemp linter fibers, prepared by batch mixing and plasticized with poly(ethylene glycol) (PEG; weight-average molecular weight 1000 g/mol), were examined by differential scanning calorimetry, thermogravimetric analysis, and mechanical tests. The properties of samples of PLA/hemp and PLA–PEG/hemp composites were analyzed as a function of the fiber amount. The thermogravimetric analysis of the composites, carried out in air, showed that the degradation process of fiber-filled systems started earlier than that of plain PLA, independently of the presence of the plasticizer. Mechanical tests showed that the property of the composites have been enhanced increased with the hemp content. The mechanical performance high-point of composites appear with count of hemp linter fiber at 1%.(sample count of hemp fiber form 1% to 7%). Plasticization with PEG did not improve the tensile properties of the composites, but improve its break stress.

scholarly journals Application of Electron Microscopy for the Analysis of the Mechanical Behavior of Advanced Ceramics

1988 ◽  
Author(s):  
V. J. Tennery ◽  
L. F. Allard ◽  
T. A. Nolan ◽  
M. H. Rawlins
Keyword(s):  
Electron Microscopy ◽  
Mechanical Behavior ◽  
Room Temperature ◽  
Mechanical Tests ◽  
Test Methods ◽  
Fatigue Tests ◽  
Flexural Test ◽  
Transmission Electron ◽  
Property Data ◽  
Nitride Ceramics

The microstructure and fracture surfaces of two commercially available silicon nitride ceramics have been characterized using techniques of scanning and analytical transmission electron microscopy. These results have been correlated to mechanical property data (obtained from static and dynamic fatigue tests using four-point flexural test methods both at room temperature and at elevated temperature). For one of the materials, the results clarified failure mechanisms. For the other, the results showed how processing variables can affect microstructure (and thus mechanical behavior), and emphasized particularly that mechanical tests of billet-derived specimens may be unreliable in predicting the mechanical behavior of production components.

Asphalt Modified by Partially Hydrogenated SBS Tri-Block Copolymers

2005 ◽  
Vol 78 (4) ◽  
pp. 620-643 ◽  
Author(s):  
M. A. Vargas ◽  
A. E. Chávez ◽  
R. Herrera ◽  
O. Manero
Keyword(s):  
High Temperature ◽  
Block Copolymers ◽  
Gel Permeation Chromatography ◽  
Mechanical Tests ◽  
Polymer Composition ◽  
Scanning Calorimetry ◽  
Styrene Butadiene Styrene ◽  
Hydrogenation Time ◽  
Styrene Butadiene ◽  
Butadiene Styrene

Abstract This work examines the modification of asphalt with hydrogenated poly (styrene-butadiene-styrene) copolymer containing different amounts of butadiene and ethylene-co-butylene. The polymer composition can be described generically as poly (styrene−[(butadiene)1−x−(ethylene−co−butylene)x]−styrene), where x is the hydrogenated fraction of the molecule. These hydrogenated (SBEBS) copolymers were produced by in-situ hydrogenation following a Ziegler-Natta catalytic reaction of poly (styrene-butadiene-styrene) tri-block copolymers (SBS), which were previously synthesized by anionic polymerization. Control over the hydrogenation time produces SBEBS polymers with various degrees of saturation of the polybutadiene block, as characterized by FTIR, HNMR, differential scanning calorimetry (DSC) and gel permeation chromatography (GPC). Polymer-modified asphalts (PMA) were obtained by a high-temperature mixing process with AC-20 asphalt (Salamanca, Mexico) and SBS or SBEBS copolymers. PMA samples were characterized before and after high-temperature storage tests by fluorescence microscopy, rheometry, and mechanical tests. Results indicate that PMA obtained from SBEBS contain a polymer matrix with well-dispersed asphalt rich phase, with improved mechanical and thermal stability over those PMA produced with SBS. Compatibility between SBEBS and the aromatic fraction of maltenes can explain the dispersion of the polymer in asphalt and the enhanced properties.

scholarly journals On the Use of Paper Sludge as Filler in Biocomposites for Injection Moulding

Materials ◽  
2021 ◽  
Vol 14 (10) ◽  
pp. 2688
Author(s):  
Vito Gigante ◽  
Patrizia Cinelli ◽  
Marco Sandroni ◽  
Roberto D’ambrosio ◽  
Andrea Lazzeri ◽  
...  
Keyword(s):  
Injection Moulding ◽  
Mechanical Performance ◽  
Impact Resistance ◽  
Mechanical Tests ◽  
Lepidium Sativum ◽  
Poly Lactic Acid ◽  
Paper Sludge ◽  
Scanning Calorimetry ◽  
Twin Screw ◽  
Acetyl Tributyl Citrate

The potential use of paper sludge (PS) as filler in the production of bio-composites based on poly lactic acid (PLA) and polybutylene adipate terephthalate (PBAT) was investigated. PS/PLA/PBAT composites, with addition of acetyl tributyl citrate (ATBC) as biobased plasticizer, were produced with PS loadings up to 30 wt.% by twin-screw extrusion followed by injection moulding. The composites were characterized by rheological measurements, thermogravimetric analysis (TGA), differential scanning calorimetry (DSC) and mechanical tests (tensile and impact resistance) to study the effect of PS on the processability, thermal stability, crystallinity and mechanical performance of polymeric matrix. The optimized composites at higher PS content were successfully processed to produce pots for horticulture and, in view of this application, preliminary phytotoxicity tests were conducted using the germination test on Lepidium sativum L. seeds. Results revealed that developed composites up to 30 wt.% PS had good processability by extrusion and injection moulding showing that PS is a potential substitute of calcium carbonate as filler in the production of bio-composites, and the absence of phytotoxic effects showed the possibility of their use in the production of pots/items for applications in floriculture and/or horticulture.

Investigation and Comparison of Aging Effects in SAC305 and Doped SAC+X Solders Exposed to Isothermal Aging

2020 ◽  
Author(s):  
Jing Wu ◽  
Mohammad S. Alam ◽  
KM Rafidh Hassan ◽  
Jeffrey C. Suhling ◽  
Pradeep Lall
Keyword(s):  
Mechanical Properties ◽  
Solid Solution ◽  
High Temperature ◽  
Mechanical Behavior ◽  
Isothermal Aging ◽  
Solder Joints ◽  
Lead Free ◽  
Aging Effects ◽  
Solid Solution Strengthening ◽  
Solution Strengthening

Abstract Microstructural evolution occurs in lead free Sn-Ag-Cu (SAC) solder joints exposed to isothermal aging. Such changes lead to degradations in the mechanical properties and creep behavior of the solder, and can result in dramatic reductions in the board level reliability of lead-free electronic assemblies subjected to aging. In our recent research, Scanning Electron Microscopy (SEM) has been used to: (1) monitor aging induced microstructural changes occurring within fixed regions in selected lead-free solder joints, (2) create time-lapse imagery of the microstructure evolution, and (3) analyze the microstructural changes quantitatively and correlate to the observed mechanical behavior evolution. This approach has removed the limitations of many prior studies where aged and non-aged microstructures were taken from two different samples and could only be qualitatively compared. In our current study, the microstructural evolutions were observed in SAC305 (96.5Sn-3.0Ag-0.5Cu) and SAC_Q (SAC+Bi) exposed to isothermal conditions at T = 100 °C and 125 °C for several different regions from several different joints. The microstructures in several fixed regions of interest were recorded after predetermined time intervals of aging, which were 1 hour (up to 270 hours) and 250 hours (up to 7000 hours) for the long-term aging samples. The aging induced changes in microstructure have been correlated with the changes in mechanical behavior measured using uniaxial tensile testing. The area and diameter of each IMC particle were tracked during the aging process using the recorded images and imaging processing software. As expected, the analysis of the evolving SAC305 and SAC+X microstructures showed a significant amount of diffusion of silver and bismuth in the beta-tin matrix during aging. In particular, Ag3Sn particles coalesced during aging leading to a decrease in the number of particles. Any bismuth in the SAC+X microstructure was observed to quickly go into solution, resulting in solid solution strengthening. This primary occurred within the beta-Sn dendrites, but also in the Ag3Sn intermetallic rich regions between dendrites. The presence of bismuth in was also found to slow the diffusion process that coarsens the Ag3Sn IMC particles. The combination solid solution strengthening and a lower diffusion rate for Ag lead to reduced aging effects in the SAC+Bi alloy relative to the SAC305 solder alloy. The SAC_Q alloy was found to have significantly better high temperature mechanical properties relative to SAC305 at all prior aging conditions. In particular, the initial modulus and ultimate tensile strength of SAC305 experienced large degradations during high temperature aging, whereas the same properties of SAC_Q changed only slightly. These changes in mechanical behavior correlated well with the observed increases in the average IMC particle diameter and decreases in the number of IMC particles. The microstructural and material property degradations were especially large for SAC305 during the initial 50 hours of aging.

Evolution of Mechanical Properties and Microstructure in SAC Bulk Solder and Solder Joints During Thermal Cycling Exposures

2021 ◽  
Author(s):  
S. M. Kamrul Hasan ◽  
Abdullah Fahim ◽  
Mohammad Al Ahsan ◽  
Jeffrey C. Suhling ◽  
Sa'd Hamasha ◽  
...  
Keyword(s):  
Mechanical Properties ◽  
High Temperature ◽  
Thermal Cycling ◽  
Mechanical Behavior ◽  
Solder Joints ◽  
Bulk Solder ◽  
Temperature Extreme ◽  
Free Condition ◽  
Elapsed Time ◽  
Solder Balls

Abstract Electronic packages are frequently exposed to thermal cycling during their service life between low to high temperature extreme. Similar phenomena can be observed in solder joints during the characterization of thermal-mechanical fatigue behavior. This variation in temperature causes the evolution of mechanical and microstructural behavior of solder joints. Also, dwelling at high temperature extreme causes the mechanical properties reduction of solder joints due to thermal aging phenomena which eventually leads to the change in microstructure. In literature, the effect of thermal aging on the mechanical behavior evolution has been reported by several research groups, but the evolution of mechanical and microstructural properties under different thermal cycling exposure is limited. In our prior study, reduction of mechanical properties of SAC305 lead-free solder material under different thermal cycling exposures have been reported for up to 5 days of thermal cycling. It was found that thermal cycling with long ramp period and dwell time has severe effect on mechanical properties reduction. In our present study, previous study has been extended up to 100 days along with the mechanical behavior evolution of solder joints under stress free condition at different thermal cyclic loading. Particularly, the evolutions of mechanical behavior in both bulk SAC305 miniature solder bar samples and small SAC305 solder balls under stress free condition have been investigated for several thermal cycling profiles, and then the results were compared. Reflow solidification technique with a controlled temperature profile has been used to prepare bulk solder specimens for uniaxial tensile testing. Optical microscopy has been used to figure out the single grain BGA solder balls after grounding and polishing to avoid grain orientation effect during nanoindentation technique. Then, both bulk solder bars and solder balls were thermally cycled between −40 C to +125 °C under a stress-free condition (no load) in a thermal chamber. Several thermal loading were adopted such as (1) 150 minutes cycles with 45 minutes ramps and 30 minutes dwells, (2) air-to-air thermal shock exposures with 30 minutes dwells and near instantaneous ramps, (3) 90 minute cycles with 45 minutes ramps and 0 minutes dwells (thermal ramp only), and (4) Isothermal aging at high temperature extreme (no cycle). After each thermal cycling exposure, mechanical properties evolution of both solder bars and solder balls were recorded in terms of effective elastic modulus (E), hardness (H), yield strength (YS), and ultimate tensile strength (UTS). For the BGA solder balls, the evolution of mechanical properties was measured using nanoindentation. Moreover, mechanical properties evolution of both specimens was compared in terms of normalized properties with respect to elapsed time under different thermal cycling exposures. Finally, the microstructural evolution of bulk solder bars was observed under slow thermal cycling exposures with elapsed time.

Application of TEM to Deformation, Wear, and Fracture of Ceramics

1974 ◽  
Vol 32 ◽  
pp. 472-473
Author(s):  
B. J. Hockey
Keyword(s):  
Wear Resistance ◽  
High Temperature ◽  
Mechanical Behavior ◽  
Brittle Materials ◽  
High Temperature Strength ◽  
Wide Range ◽  
Corrosive Environments ◽  
Further Development

Ceramics, such as Al2O3 and SiC have numerous current and potential uses in applications where high temperature strength, hardness, and wear resistance are required often in corrosive environments. These materials are, however, highly anisotropic and brittle, so that their mechanical behavior is often unpredictable. The further development of these materials will require a better understanding of the basic mechanisms controlling deformation, wear, and fracture.The purpose of this talk is to describe applications of TEM to the study of the deformation, wear, and fracture of Al2O3. Similar studies are currently being conducted on SiC and the techniques involved should be applicable to a wide range of hard, brittle materials.

Structures of chemically stabilized ceramics

1993 ◽  
Vol 51 ◽  
pp. 924-925
Author(s):  
Pratibha L. Gai ◽  
M. A. Saltzberg ◽  
L.G. Hanna ◽  
S.C. Winchester
Keyword(s):  
High Temperature ◽  
Calcium Nitrate ◽  
Nitrate Hexahydrate ◽  
Chemical Route ◽  
Cubic Form ◽  
Tetragonal Form ◽  
Wet Chemical ◽  
Wet Chemical Route ◽  
Final Composition ◽  
Aluminium Nitrate Nonahydrate

Silica based ceramics are some of the most fundamental in crystal chemistry. The cristobalite form of silica has two modifications, α (low temperature, tetragonal form) and β (high temperature, cubic form). This paper describes our structural studies of unusual chemically stabilized cristobalite (CSC) material, a room temperature silica-based ceramic containing small amounts of dopants, prepared by a wet chemical route. It displays many of the structural charatcteristics of the high temperature β-cristobalite (∼270°C), but does not undergo phase inversion to α-cristobalite upon cooling. The Structure of α-cristobalite is well established, but that of β is not yet fully understood.Compositions with varying Ca/Al ratio and substitutions in cristobalite were prepared in the series, CaO:Al2O3:SiO2 : 3-x: x : 40, with x= 0-3. For CSC, a clear sol was prepared from Du Pont colloidal silica, Ludox AS-40®, aluminium nitrate nonahydrate, and calcium nitrate hexahydrate in proportions to form a final composition 1:2:40 composition.

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