Effect of Mean Temperature on the Evolution of Strain-Amplitude in SAC Ball-Grid Arrays during Operation under Thermal Aging and Temperature Excursions

2017 ◽  
Author(s):  
Pradeep Lall ◽  
Kazi Mirza ◽  
Jeff Suhling ◽  
David Locker
Keyword(s):  
Strain Amplitude ◽  
Thermal Aging ◽  
Ball Grid Arrays ◽  
Mean Temperature

scholarly journals Effects of Thermal Aging on the Low Cycle Fatigue Behaviors of Cast Duplex Stainless Steels

Metals ◽  
2019 ◽  
Vol 9 (3) ◽  
pp. 378 ◽  
Author(s):  
Shilei Li ◽  
Yanli Wang ◽  
Xitao Wang
Keyword(s):  
Fatigue Life ◽  
Strain Amplitude ◽  
Thermal Aging ◽  
High Strain ◽  
Low Cycle Fatigue ◽  
Cycle Fatigue ◽  
Premature Failure ◽  
High Strain Amplitude ◽  
Cleavage Cracking ◽  
Fracture Morphologies

The low cycle fatigue (LCF) behaviors of cast duplex stainless steel (CDSS) thermally aged at different times were investigated under different strain amplitudes. The effects of thermal aging on the LCF lives of CDSS are closely related to the strain amplitude. At a low strain amplitude, the fatigue life of the material increases significantly after thermal aging, while the LCF life decreases with an increasing aging time at a high strain amplitude. After thermal aging at 400 °C for 10,000 h, the fatigue fracture morphologies of CDSS change from fatigue fringes to mixture features including fatigue fringes in austenite and cleavage cracks in ferrite. Severe plastic deformation in ferrite of the aged CDSS under a high strain amplitude causes the cleavage cracking of ferrite. The premature failure of ferrite accelerates the propagation of fatigue crack and shortens the fatigue life at a high strain amplitude.

A Novel Approach to Front-Side Deprocessing for Thinned Die after Backside Failure Isolation

2003 ◽  
Author(s):  
Dat Nguyen ◽  
Cuong Phan ◽  
Jeff Conner ◽  
Martin Smith ◽  
John Drummond
Keyword(s):  
Front Side ◽  
Ball Grid Arrays ◽  
Safe Handling ◽  
Flip Chips ◽  
Novel Approach ◽  
Diamond Saw ◽  
Reconstructed Sample

Abstract This paper describes a novel approach for safe handling of the thinned die from the front; a technique that can also be successfully applied to preserve cracked die. The discussion provides details on the characteristics and processes involved in backside reconstruction, thinned die reconstruction, and front-side deprocessing of thinned die. The finished backside reconstruction sample was cross-sectioned for examination using a diamond saw. After 6 hours of bake, no cracking of the thinned die was observed. Front-side deprocessing was then applied to the backside reconstructed sample. The sample remains intact. The technique has proven to be easily applied and highly reliable, and provides a solution for front-side deprocessing for both high pin count ball grid arrays and flip chips.

scholarly journals Contrasting Evolution Patterns of Endorheic and Exorheic Lakes on the Central Tibetan Plateau and Climate Cause Analysis during 1988–2017

Water ◽  
2021 ◽  
Vol 13 (14) ◽  
pp. 1962
Author(s):  
Zhilong Zhao ◽  
Yue Zhang ◽  
Zengzeng Hu ◽  
Xuanhua Nie
Keyword(s):  
Climate Change ◽  
Tibetan Plateau ◽  
Climatic Factors ◽  
Global Climate ◽  
Rapid Expansion ◽  
Annual Precipitation ◽  
The Tibetan Plateau ◽  
Lake Area ◽  
Climate Change Research ◽  
Mean Temperature

The alpine lakes on the Tibetan Plateau (TP) are indicators of climate change. The assessment of lake dynamics on the TP is an important component of global climate change research. With a focus on lakes in the 33° N zone of the central TP, this study investigates the temporal evolution patterns of the lake areas of different types of lakes, i.e., non-glacier-fed endorheic lakes and non-glacier-fed exorheic lakes, during 1988–2017, and examines their relationship with changes in climatic factors. From 1988 to 2017, two endorheic lakes (Lake Yagenco and Lake Zhamcomaqiong) in the study area expanded significantly, i.e., by more than 50%. Over the same period, two exorheic lakes within the study area also exhibited spatio-temporal variability: Lake Gaeencuonama increased by 5.48%, and the change in Lake Zhamuco was not significant. The 2000s was a period of rapid expansion of both the closed lakes (endorheic lakes) and open lakes (exorheic lakes) in the study area. However, the endorheic lakes maintained the increase in lake area after the period of rapid expansion, while the exorheic lakes decreased after significant expansion. During 1988–2017, the annual mean temperature significantly increased at a rate of 0.04 °C/a, while the annual precipitation slightly increased at a rate of 2.23 mm/a. Furthermore, the annual precipitation significantly increased at a rate of 14.28 mm/a during 1995–2008. The results of this study demonstrate that the change in precipitation was responsible for the observed changes in the lake areas of the two exorheic lakes within the study area, while the changes in the lake areas of the two endorheic lakes were more sensitive to the annual mean temperature between 1988 and 2017. Given the importance of lakes to the TP, these are not trivial issues, and we now need accelerated research based on long-term and continuous remote sensing data.

Sign in / Sign up

Export Citation Format

Share Document