Effect of Aging on Impression Creep Behavior of Pb-Free Solders

2013 ◽  
Author(s):  
B. Talebanpour ◽  
U. Sahaym ◽  
I. Dutta ◽  
P. Kumar
Keyword(s):  
Creep Behavior ◽  
Impression Creep ◽  
Creep Properties ◽  
Particle Spacing ◽  
Ag3sn Particle ◽  
Creep Stress ◽  
Microstructural Coarsening ◽  
Creep Stress Exponent ◽  
Sac Solder

During service and/or storage, Sn-Ag-Cu (SAC) solder alloys are subjected to temperatures ranging from 0.4 to 0.8 Tm (where Tm is the melting temperature of SAC alloys), making them highly prone to significant microstructural coarsening. The microstructures of these low melting point alloys continuously evolve during service. This results in evolution of creep properties of the joint over time, thereby influencing the long-term reliability of microelectronic packages. Here, we study microstructure evolution and creep behavior of two Sn-Ag-Cu (SAC) alloys, namely Sn-3.0Ag-0.5Cu and Sn-1.0Cu-0.5Cu, isothermally aged at 150°C for various lengths of time. Creep behavior of the two SAC solders after different aging durations was systematically studied using impression creep technique. The key microstructural features that evolve during aging are Ag3Sn particle size and inter-particle spacing. Creep results indicate that the creep rate increases considerably with increasing inter-particle spacing although the creep stress exponent and creep activation energy are independent of the aging history.

Grain Size Effect on the Creep Behavior of Monolithic MoSi2

1994 ◽  
Vol 364 ◽  
Author(s):  
C.R. Feng ◽  
K. Sadananda
Keyword(s):  
Grain Size ◽  
Size Effect ◽  
Stress Exponent ◽  
Creep Behavior ◽  
Molybdenum Disilicide ◽  
Grain Size Effect ◽  
Stress Range ◽  
Creep Stress ◽  
Creep Stress Exponent

AbstractThe grain size effect on the creep behavior of hot-pressed monolithic molybdenum disilicide was investigated at 1200°C in a 19–255 MPa stress range. The creep-stress exponent, n, increased from 1 at low stresses to 4 at high stresses. The grain size exponent, p, varied from 0, to 3.5 and to 8 depending on the grain size, the creep-stress exponent, and creep history.

Effect of Tungsten on Long-Term Microstructural Evolution and Impression Creep Behavior of 9Cr Reduced Activation Ferritic/Martensitic Steel

2016 ◽  
Vol 48 (1) ◽  
pp. 425-438 ◽  
Author(s):  
V. Thomas Paul ◽  
V. D. Vijayanand ◽  
C. Sudha ◽  
S. Saroja
Keyword(s):  
Microstructural Evolution ◽  
Creep Behavior ◽  
Martensitic Steel ◽  
Impression Creep

Effects of a layered structure on the physicomechanical properties and extended creep behavior of bamboo-polypropylene composites (BPCs) determined by the stepped isostress method

Holzforschung ◽  
2018 ◽  
Vol 72 (7) ◽  
pp. 589-597 ◽  
Author(s):  
Chin-Yin Hsu ◽  
Teng-Chun Yang ◽  
Tung-Lin Wu ◽  
Ke-Chang Hung ◽  
Jyh-Horng Wu
Keyword(s):  
Creep Behavior ◽  
Bottom Layer ◽  
Short Term ◽  
Creep Properties ◽  
Polypropylene Composites ◽  
Plastic Composite ◽  
Accelerated Creep ◽  
Term Creep ◽  
Better Than

AbstractA layered bamboo-plastic composite (BPC) consisting of bamboo (Phyllostachys makinoi) particles and polypropylene was investigated. The influence of the layering conditions, including the thickness and bamboo content in various layers, was the focus in terms of the physicomechanical and creep properties of the BPCs. The results showed that a three-layered BPC (BPC3L) with a 1:3:1 thickness ratio and with top/bottom layer containing 40% bamboo exhibited the best specific flexural properties. An accelerated creep test approach was applied, known as the short-term stepped isostress method (SSM), to predict the long-term creep behavior of BPC3L. The results indicated that the creep master curves, which are constructed from different SSM testing parameters, agree well with the long-term experimental creep data and that the creep resistance of homogeneous single-layered BPC was better than that of BPC3L.

Rate Equations for Elevated Temperature Creep

1979 ◽  
Vol 101 (4) ◽  
pp. 396-402 ◽  
Author(s):  
P. P. Pizzo
Keyword(s):  
Creep Behavior ◽  
Steady State Creep ◽  
Rate Equations ◽  
Steady State Creep Rate ◽  
Creep Properties ◽  
Rate Dependent ◽  
Predicting Performance ◽  
Major Transition ◽  
Definition Of

Creep deformation is characterized in terms of temperature, the applied load and the resultant steady-state creep rate. A correlation is often sought to describe accelerated test data and to provide a means of predicting performance in service. Since prediction often involves extrapolation outside the data range, there is concern for possible transitions in creep behavior. Rate dependent transitions in creep behavior are common for many commercial alloys, and research over the years has provided an understanding of some of the basic mechanisms involved. This understanding has led to definition of conditions under which different mechanisms are active and, thus, bounds at which transitions will occur. In this paper, the major transition mechanisms are briefly discussed and their significance to long-term extrapolation of creep properties is demonstrated.

In Situ Tests on Creep Behavior of Rock Mass with Joint or Shearing Zone in Foundation of Large-Scale Hydroelectric Projects

2004 ◽  
Vol 261-263 ◽  
pp. 1097-1102 ◽  
Author(s):  
Jian Liu ◽  
Xia Ting Feng ◽  
Xiu Li Ding ◽  
Huo Ming Zhou
Keyword(s):  
Rock Mass ◽  
Creep Behavior ◽  
Large Scale ◽  
Time Dependent ◽  
Three Gorges Project ◽  
Three Gorges ◽  
The Three Gorges ◽  
The Three Gorges Project

The time-dependent behavior of rock mass, which is generally governed by joints and shearing zones, is of great significance for engineering design and prediction of long-term deformation and stability. In situ creep test is a more effective method than laboratory test in characterizing the creep behavior of rock mass with joint or shearing zone due to the complexity of field conditions. A series of in situ creep tests on granite with joint at the shiplock area of the Three-Gorges Project and basalt with shearing zone at the right abutment of the Xiluodu Project were performed in this study. Based on the test results, the stress-displacement-time responses of the joints and basalt are analyzed, and their time-dependent constitutive model and model coefficients are given, which is crucial for the design to prevent the creep deformations of rock masses from causing the failure of the operation of the shiplock gate at the Three-Gorges Project and long-term stability of the Xiluodu arc dam.

Indenter misalignment in impression creep test: Uncertainty, correction and recommendation

2021 ◽  
pp. 030932472199765
Author(s):  
Suo Li ◽  
Dean Deng ◽  
Wei Sun
Keyword(s):  
Creep Test ◽  
Vertical Direction ◽  
Steady State Creep ◽  
Impression Creep ◽  
Finite Element Analyses ◽  
Empirical Formulas ◽  
Test Technique ◽  
Creep Properties ◽  
Miniature Specimen ◽  
Specimen Test

The impression creep test (ICT) method, as a miniature specimen test technique, has been used extensively to determine the in-service creep properties of power plant components. However, the experiment results of the ICT can be affected by some uncertainties associated with the inaccuracies of measurement, which have not been studied before. This paper presents some results of finite element analyses, to evaluate the effect of indenter misalignment on the results of the ICT, such as the steady-state creep deformation rate and the conversion parameters. The results obtained have shown that the angular misalignments of the indenter around horizontal directions have a relatively significant influence on the conversion parameters, and the misalignment around vertical direction has a much less significant effect. Empirical formulas were developed for the possible correction of the conversion factors. Finally, some recommendations on the control of the indenter and specimen alignment were given.

scholarly journals Effect of long-term thermal exposure on microstructure and creep properties of DD5 single crystal superalloy

China Foundry ◽  
2021 ◽  
Vol 18 (3) ◽  
pp. 185-191
Author(s):  
Xu-dong Wang ◽  
Zhong Yang ◽  
Qiang Gao ◽  
Li-rong Liu
Keyword(s):  
Single Crystal ◽  
Thermal Exposure ◽  
Single Crystal Superalloy ◽  
Creep Properties

Prediction of Long-Term Creep Properties of Zirconium-2.5 % Niobium Alloy Using Wilshire Method

2021 ◽  
Vol 10 (2) ◽  
pp. 20200146
Author(s):  
Vivek Patel ◽  
R. N. Singh ◽  
Madangopal Krishnan
Keyword(s):  
Niobium Alloy ◽  
Creep Properties ◽  
Term Creep

scholarly journals Influence of Long Term Ageing and Superimposed Creep Stress on the Microstructure of 1 mass%Cr-0.5 mass%Mo Steel

1992 ◽  
Vol 33 (2) ◽  
pp. 110-119 ◽  
Author(s):  
N. Gope ◽  
T. Mukherjee ◽  
D. S. Sarma
Keyword(s):  
Creep Stress

Long-term creep behavior of 9–12%Cr power plant steels

2003 ◽  
Vol 51 (1) ◽  
pp. 35-48 ◽  
Author(s):  
V Sklenicka
Keyword(s):  
Power Plant ◽  
Creep Behavior ◽  
Term Creep
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