Effect of Moisture on Fracture Toughness of Composite/Wood Bonded Interfaces

2008 ◽  
pp. 526-526-19 ◽  
Author(s):  
P Qiao ◽  
JF Davalos ◽  
BS Trimble
Keyword(s):  
Fracture Toughness ◽  
Effect Of Moisture ◽  
Composite Wood

Effect of Moisture on the Interfacial Adhesion of the Underfill/Solder Mask Interface

2002 ◽  
Vol 124 (2) ◽  
pp. 106-110 ◽  
Author(s):  
Timothy Ferguson ◽  
Jianmin Qu
Keyword(s):  
Fracture Toughness ◽  
Interfacial Adhesion ◽  
Interfacial Fracture ◽  
Interfacial Fracture Toughness ◽  
Interfacial Toughness ◽  
Solder Mask ◽  
Effect Of Moisture ◽  
Point Bend ◽  
Four Point Bend Test

Moisture poses a significant threat to the reliability of microelectronic assemblies and can be attributed as being the principal cause of many premature package failures. Of particular concern is characterizing the role of moisture with respect to the acceleration of the onset of package delamination. In this paper the effect of moisture on the interfacial fracture toughness of two no-flow underfill materials with a commercially available solder mask coated FR-4 board is experimentally determined. Bilayer specimens with prefabricated interface cracks are used in a four-point bend test to quantify the interfacial fracture toughness. Two groups of test specimens of varying underfill thickness were constructed. The first group was fully dried while the other was moisture preconditioned at 85°C/85%RH for 725 hours. The results of this study show that the interfacial toughness is significantly affected by the presence of moisture.

Mode I Fracture Toughness of Fiber Reinforced Composite-Wood Bonded Interface

1998 ◽  
Vol 32 (10) ◽  
pp. 987-1013 ◽  
Author(s):  
Julio F. Davalos ◽  
Pizhong Qiao ◽  
Prabhu Madabhusi-Raman ◽  
Elemer M. Lang
Keyword(s):  
Fracture Toughness ◽  
Mode I ◽  
Fiber Reinforced ◽  
Fiber Reinforced Composite ◽  
Mode I Fracture ◽  
Mode I Fracture Toughness ◽  
Reinforced Composite ◽  
Bonded Interface ◽  
Composite Wood

Effect of Moisture on the Elastic Modulus and Interfacial Adhesion of Polymer-Metal Components in Microelectronic Assemblies

2003 ◽  
Author(s):  
Timothy P. Ferguson ◽  
Jianmin Qu
Keyword(s):  
Fracture Toughness ◽  
Elastic Modulus ◽  
Interfacial Adhesion ◽  
Interfacial Fracture ◽  
Moisture Diffusivity ◽  
Bending Test ◽  
Interfacial Fracture Toughness ◽  
Moisture Concentration ◽  
Polymer Metal ◽  
Effect Of Moisture

Moisture poses a significant threat to the reliability of microelectronic assemblies and can be attributed as being one of the principal causes of many premature package failures. It is a multi-dimensional concern in electronic packaging, having an adverse effect on package reliability by changing both the mechanical properties and interfacial adhesion of the microelectronic assembly. In this paper, a study has been conducted to evaluate the moisture-induced degradation of both the elastic modulus of a commercially available no-flow underfill and the interfacial adhesion of the underfill to a copper alloy substrate. Three different levels of moisture preconditioning, 85C/50%RH, 85C/65%RH, and 85C/85RH%, were implemented in this study. Diffusion coefficient test specimens were constructed to experimentally measure the moisture diffusivity into the underfill resin and obtain the moisture saturation concentration for each level of moisture preconditioning. Flexural bend test specimens were made to characterize the effect of moisture on the elastic modulus of the underfill adhesive. Last, interfacial fracture toughness specimens with prefabricated interface cracks were used in a four point bending test to quantify the effect of moisture on interfacial fracture toughness. The results of this study will aid in the development of more robust microelectronic assemblies, demonstrating how both the elastic modulus and interfacial toughness change as a function of moisture concentration.

Precipitation in Al-Li-Zr alloys

1992 ◽  
Vol 50 (1) ◽  
pp. 186-187
Author(s):  
D.M. Vanderwalker
Keyword(s):  
Fracture Toughness ◽  
Precipitation Hardening ◽  
Weight Ratio ◽  
High Strength ◽  
Transmission Electron ◽  
Water Quench ◽  
Aluminum Lithium ◽  
Aluminum Lithium Alloys ◽  
Lithium Alloys ◽  
Zr Alloys

Aluminum-lithium alloys have a low density and high strength to weight ratio. They are being developed for the aerospace industry.The high strength of Al-Li can be attributed to precipitation hardening. Unfortunately when aged, Al-Li aquires a low ductility and fracture toughness. The precipitate in Al-Li is part of a sequence SSSS → Al3Li → AlLi A description of the phases may be found in reference 1 . This paper is primarily concerned with the Al3Li phase. The addition of Zr to Al-Li is being explored to find the optimum in properties. Zirconium improves fracture toughness and inhibits recrystallization. This study is a comparision between two Al-Li-Zr alloys differing in Zr concentration.Al-2.99Li-0.17Zr(alloy A) and Al-2.99Li-0.67Zr (alloy B) were solutionized for one hour at 500oc followed by a water quench. The specimens were then aged at 150°C for 16 or 40 hours. The foils were punched into 3mm discs. The specimens were electropolished with a 1/3 nitric acid 2/3 methanol solution. The transmission electron microscopy was conducted on the JEM 200CX microscope.

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