Improvements of microstructure, wettability, tensile and creep strength of eutectic Sn–Ag alloy by doping with rare-earth elements

2002 ◽  
Vol 17 (12) ◽  
pp. 3146-3154 ◽  
Author(s):  
C. M. L. Wu ◽  
D. Q. Yu ◽  
C. M. T. Law ◽  
L. Wang
Keyword(s):  
Rare Earth ◽  
Creep Resistance ◽  
Interface Energy ◽  
Melting Behavior ◽  
Tensile Creep ◽  
Scanning Calorimetry ◽  
Wetting Properties ◽  
Solder Flux ◽  
Free Solder ◽  
Re Elements

To improve the properties of the eutectic Sn–Ag lead-free solder alloy, various amounts of mixed rare-earth (RE) elements, mainly Ce and La, were added. The microstructure, wetting properties, melting behavior, mechanical properties, and creep behavior were studied. It was revealed that RE elements can refine the intermetallics, and with 0.5% RE addition, the RE-bearing phase can be detected in the microstructure of the slow-cooled alloy. The results of differential scanning calorimetry indicate that the melting points of the RE-doped alloys are slightly lower than that of the Sn–3.5Ag and have a eutectic peak. The wetting property and creep resistance of the Sn–3.5Ag–0.25RE alloy are better than those of the Sn–3.5Ag alloy. The creep properties were studied at the temperatures of 303, 348, and 393 K, at various stress levels between 8 and 34 MPa. The stress exponents of the Sn–3.5Ag and Sn–3.5Ag–0.25RE were obtained at these temperatures. Tensile, creep, and wetting properties were found to improve with the addition of RE elements. The improvement of creep resistance is due to the fine dispersion of intermetallics and the decrease in interface energy between matrix and intermetallics. The wettability improvement is mainly due to the accumulation of RE elements at the solder/flux interface, leading to the reduction of the interfacial tension between solder and flux.

scholarly journals Modification in Bi-Ag Lead-Free Solder-Bearing Alloying Elements

2018 ◽  
Vol 14 (2) ◽  
pp. 5504-5519 ◽  
Author(s):  
Rizk Mostafa Shalaby ◽  
Musaeed Allzeleh ◽  
Mustafa Kamal
Keyword(s):  
Rare Earth ◽  
Electrical Resistance ◽  
Creep Resistance ◽  
Melting Behavior ◽  
Lead Free ◽  
Lead Free Solder ◽  
Soldering Temperature ◽  
Urgent Task ◽  
Free Solder ◽  
Lead Free Solders

The development of lead-free solder has an urgent task for material scientist due to health and environmental concerns over the lead content of traditional solders. The objective of this study is to examine Bi-Ag-rare earth (RE) element considered as one of the more attractive lead-free solders since it can easily replace Sn-Pb eutectic alloy with increasing soldering temperature while causes for high-temperature applications. In order to enhance the soldering properties of Bi-Ag alloys, a trace eare earth (RE) element of Ho added into Bi-Ag alloys. The results indicated that the addition of RE led to the refining of coarse Bi-Ag grains, in the microstructure. The tensile strength, Hv and creep resistance increased with a decrease in melting point and electrical resistance. This paper brief the influences of rare earth alloying element and rapid solidification on both of the microstructure, intermetallic compounds, creep resistance, melting behavior, electrical resistance and mechanical behavior.

Investigation and Application of Excellent Performance Mg Rare Earth Alloys as a Structural Material

2007 ◽  
Vol 539-543 ◽  
pp. 1719-1722 ◽  
Author(s):  
Li Min Wang ◽  
Qiu Ming Peng ◽  
Jie Yang ◽  
Da Qing Fang ◽  
Yao Ming Wu ◽  
...  
Keyword(s):  
Rare Earth ◽  
Structural Material ◽  
Creep Resistance ◽  
Mg Alloys ◽  
Rare Earth Alloys ◽  
Excellent Performance ◽  
Specific Strength ◽  
High Specific Strength ◽  
Transmission Case ◽  
Re Elements

Magnesium (Mg) alloys are becoming one of the key engineering materials for aerospace and automotive industries because of their low density, high specific strength, excellent machinability and good diecastability, etc. In the meantime, conventional Mg alloys are limited for their low strength and creep resistance. Therefore, special attention is given on its applications at high temperature such as the transmission case and the engine block, In the near decades, much effort have been devoted to improving the properties such as strength, ductility, creep resistance of Mg alloys by adding rare earth (RE) elements, and it has been certified that the addition of RE do improve the performances of the Mg alloys. In this paper, we will review the progresses in the investigations of the Mg-RE alloys as a structural material, and also propose its application prospect in future.

Effect of rapid solidification on microstructure, creep resistance and thermal properties of Sn-10 wt.% Sb- 3 wt.% X ( X= In, Ag, Bi and Zn) lead-free solder alloys

2015 ◽  
Vol 9 (1) ◽  
pp. 2287-2298
Author(s):  
Rizk Mostafa Shalaby
Keyword(s):  
Grain Size ◽  
Intermetallic Compound ◽  
Creep Resistance ◽  
Melt Spinning ◽  
Microstructural Analysis ◽  
Lead Free ◽  
Lead Free Solder ◽  
Scanning Calorimetry ◽  
Hardness Tester ◽  
Free Solder

AbstractThe harmful effects of lead on the environment and human health, coupled with the threat of legislation, have prompted a serious search for lead-free solders for electronic packaging applications. The melt-spinning processes of ternary Sn-10 wt.%Sb-3 wt.%X (X=In, Ag, Bi and Zn) were analyzed using x-ray diffractometer (XRD), scanning electron microscopy (SEM), differential scanning calorimetry (DSC) and Vickers hardness tester (HV). The investigation showed that, the addition of a small amount of the third element enhances the ductility of the Sn–10 wt.% Sb lead-free solder due to the formation of a fine, homogeneous ternary microstructure.. It is concluded that, the addition of 3.0 wt% Ag improves the grain size of the ternary microstructure. Moreover, SnSb intermetallic compound, precipitated finely from the solid tin solution near the grain boundaries with antimony. This fine precipitated intermetallic compound suppresses the coarsening of the ternary structure and thus enhances solder ductility. Structural and microstructural analysis revealed that the origin of change in mechanical behaviors was due to refined beta-Sn grains and formation of intermetallic compounds (IMCs) SnSb, InSn19, β-In3Sn and Ag3Sn. The results indicated that the melting point of Sn-10Sb-3 wt.% Ag and Sn-10 wt.%Sb- 3 wt.% Zn alloys reduced to  230 and 240 ˚C respectively.  In particular, the zinc addition at 3 wt.%  is the most effective in improving solder ductility. The good creep resistance of Sn-10 wt.% Sb-3 wt.% Zn lead-free solder correlated to a large β-Sn grain size and complete soluble of SnSb IMC particles in the β-Sn matrix.

scholarly journals Effect of rare earth Ce on the microstructure, physical properties and thermal stability of a new lead-free solder

2011 ◽  
Vol 47 (1) ◽  
pp. 11-21 ◽  
Author(s):  
W. Chen ◽  
J. Kong ◽  
W.J. Chen
Keyword(s):  
Rare Earth ◽  
Melting Temperature ◽  
Lead Free ◽  
Lead Free Solder ◽  
Solder Alloys ◽  
Wetting Properties ◽  
Wetting Property ◽  
Cast Alloys ◽  
Free Solder ◽  
Induced Aggregation

In this paper, in order to develop a low silver content lead-free solder with good overall properties, a newly designed solder alloys of Sn-0.3Ag-0.7Cu-20Bi-xCe type, with addition of varying amounts of rare earth Ce (0.05 mass%, 0.1 mass% and 0.2 mass%) were studied. The melting temperature of Sn-0.3Ag- 0.7Cu can be decreased substantially through addition of 20 mass% Bi; while the segregation of Bi element in the microstructure of the as-cast alloys can be relieved by micro-alloying with trace amount of rare earth Ce. Besides, aging treatments (160?C held for 6 h) of these solder alloys imply that appropriate amount of Ce addition can not only depress the diffusion induced aggregation of Bi in the microstructure but promote the homogenization during annealing. Compared with Bi-free Sn-0.3Ag-0.7Cu solder, Sn-0.3Ag-0.7Cu- 20Bi exhibits better wettability. More excitingly, the wetting property of Sn-0.3Ag-0.7Cu-20Bi can be further improved by doping little amounts of Ce, especially 0.5 mass%, in which case the spreading area of the solder can be increased to the largest extent. On the whole, the present study reveals that Sn-0.3Ag-0.7Cu- 20Bi-xCe (x=0.05-0.1) is a promising lead-free solder candidate considering the microstructure, melting temperature and wetting properties.

scholarly journals Solderability, Microstructure, and Thermal Characteristics of Sn-0.7Cu Alloy Processed by High-Energy Ball Milling

Metals ◽  
2020 ◽  
Vol 10 (3) ◽  
pp. 370
Author(s):  
Ashutosh Sharma ◽  
Min Chul Oh ◽  
Myoung Jin Chae ◽  
Hyungtak Seo ◽  
Byungmin Ahn
Keyword(s):  
Ball Milling ◽  
Thermal Characteristics ◽  
Melting Behavior ◽  
High Energy ◽  
High Energy Ball Milling ◽  
Scanning Calorimetry ◽  
Wetting Properties ◽  
Energy Ball ◽  
Evolution Of Microstructure

In this work, we have investigated the role of high-energy ball milling (HEBM) on the evolution of microstructure, thermal, and wetting properties of an Sn-0.7Cu alloy. We ball-milled the constituent Sn and Cu powders in eutectic composition for 45 h. The microstructural studies were carried out using optical and scanning electron microscopy. The melting behavior of the powder was examined using differential scanning calorimetry (DSC). We observed a considerable depression in the melting point of the Sn-0.7Cu alloy (≈7 °C) as compared to standard cast Sn-0.7Cu alloys. The resultant crystallite size and lattice strain of the ball-milled Sn-0.7Cu alloy were 76 nm and 1.87%, respectively. The solderability of the Sn-0.7Cu alloy was also improved with the milling time, due to the basic processes occurring during the HEBM.

An Experimental and Modeling Investigation of Tensile Creep Resistance in a Stable Nanocrystalline Alloy

2020 ◽  
Author(s):  
C. Kale ◽  
S. Srinivasan ◽  
B.C. Hornbuckle ◽  
R.K. Koju ◽  
K. Darling ◽  
...  
Keyword(s):  
Creep Resistance ◽  
Nanocrystalline Alloy ◽  
Tensile Creep

scholarly journals Effect of rare earth oxide CeO2 on the anodic bonding performance of PEG-based MEMS encapsulation materials

2021 ◽  
Vol 13 (3) ◽  
pp. 168781402110077
Author(s):  
Chao Du ◽  
Cuirong Liu ◽  
Xu Yin ◽  
Haocheng Zhao
Keyword(s):  
Tensile Strength ◽  
Rare Earth ◽  
Rare Earth Oxide ◽  
Solid Polymer Electrolytes ◽  
Anodic Bonding ◽  
Solid Polymer ◽  
Bonding Layer ◽  
Scanning Calorimetry ◽  
Ion Migration ◽  
Bonding Performance

Herein, we synthesized a new polyethylene glycol (PEG)-based solid polymer electrolyte containing a rare earth oxide, CeO2, using mechanical metallurgy to prepare an encapsulation bonding material for MEMS. The effects of CeO2 content (0–15 wt.%) on the anodic bonding properties of the composites were investigated. Samples were analyzed and characterized by alternating current impedance spectroscopy, X-ray diffraction, scanning electron microscopy, differential scanning calorimetry, tensile strength tests, and anodic bonding experiments. CeO2 reduced the crystallinity of the material, promoted ion migration, increased the conductivity, increased the peak current of the bonding process, and increased the tensile strength. The maximum bonding efficiency and optimal bonding layer were obtained at 8 wt% CeO2. This study expands the applications of solid polymer electrolytes as encapsulation bonding materials.

RARE-EARTH DOPED POTASSIUM LEAD BROMIDE MID-IR LASER SOURCES FOR STANDOFF DETECTION

2008 ◽  
Vol 18 (03) ◽  
pp. 735-745 ◽  
Author(s):  
KRISHNA C. MANDAL ◽  
SUNG H. KANG ◽  
MICHAEL CHOI ◽  
R. DAVID RAUH
Keyword(s):  
Rare Earth ◽  
Emission Spectra ◽  
Optical Quality ◽  
Scanning Calorimetry ◽  
Laser Applications ◽  
Excellent Thermal Stability ◽  
Standoff Detection ◽  
Lead Bromide ◽  
Vertical Bridgman ◽  
Laser Crystals

The single crystal growth of KPb 2 Br 5 by vertical Bridgman technique using in-house processed zone refined PbBr 2 and KBr with rare-earth terbium doping has been studied. The grown moisture resistant crystals (1.5 cm diameter and 10 cm length) have shown high promise for low phonon energy room temperature solid-state laser applications in the longer side of mid-IR (4-15 µm) due to their high storage lifetimes, wide tunability, and excellent optical quality. The processed crystals are highly transparent ( T = ≥80%) in the 0.4-25 µm spectral region. Repeated melting-freezing cycles during differential scanning calorimetry (DSC) experiments did not reveal any appreciable variation in the melting point or phase transitions, which is indicative of their excellent thermal stability. The emission spectra pumped with a 2 µm source show broadband emissions with peak wavelength of 3 µ m (7 F 4→ 7 F6), 5µ m (7 F 5→ 7 F 6) and 7.9µ m (7 F 4→ 7 F 5). The KPb 2 Br 5: Tb laser crystals will be highly useful for standoff detection of incoming chemical and biological threats using unique infrared absorption signatures.

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