Mixed-mode ductile failure analysis of V-notched Al 7075-T6 thin sheets

2015 ◽  
Vol 150 ◽  
pp. 70-95 ◽  
Author(s):  
A.R. Torabi ◽  
M. Alaei
Keyword(s):  
Failure Analysis ◽  
Mixed Mode ◽  
Ductile Failure ◽  
Thin Sheets ◽  
Al 7075

Combine Micro-Probing and OBIRCH to Catch Non-Recognizable Fault in RF and Mixed-Mode Integrated Circuits

2007 ◽  
Author(s):  
Cha-Ming Shen ◽  
Yen-Long Chang ◽  
Lian-Fon Wen ◽  
Tan-Chen Chuang ◽  
Shi-Chen Lin ◽  
...  
Keyword(s):  
Integrated Circuits ◽  
Radio Frequency ◽  
Failure Analysis ◽  
Case Studies ◽  
Mixed Mode ◽  
Failure Mechanisms ◽  
Deep Submicron ◽  
Digital Logic ◽  
Successful Approach ◽  
Cmos Processes

Abstract Highly-integrated radio frequency and mixed-mode devices that are manufactured in deep-submicron or more advanced CMOS processes are becoming more complex to analyze. The increased complexity presents us with many eccentric failure mechanisms that are uniquely different from traditional failure mechanisms found during failure analysis on digital logic applications. This paper presents a novel methodology to overcome the difficulties and discusses two case studies which demonstrate the application of the methodology. Through the case studies, the methodology was proven to be a successful approach. It is also proved how this methodology would work for such non-recognizable failures.

scholarly journals Creep Behaviour and Microstructural Characterization of VAT 36 and VAT 32 Superalloys

Metals ◽  
2018 ◽  
Vol 8 (11) ◽  
pp. 877 ◽  
Author(s):  
Vagner Gobbi ◽  
Silvio Gobbi ◽  
Danieli Reis ◽  
Jorge Ferreira ◽  
José Araújo ◽  
...  
Keyword(s):  
Failure Analysis ◽  
Creep Resistance ◽  
High Performance ◽  
Creep Behaviour ◽  
Ductile Failure ◽  
Microstructural Characterization ◽  
Dislocation Slip ◽  
Creep Tests ◽  
Experimental Conditions ◽  
Wide Range

Superalloys are used primarily for the aerospace, automotive, and petrochemical industries. These applications require materials with high creep resistance. In this work, evaluation of creep resistance and microstructural characterization were carried out at two new nickel intermediate content alloys for application in aerospace industry and in high performance valves for automotive applications (alloys VAT 32 and VAT 36). The alloys are based on a high nickel chromium austenitic matrix with dispersion of intermetallic L12 and phases containing different (Nb,Ti)C carbides. Creep tests were performed at constant load, in the temperature range of 675–750 °C and stress range of 500–600 MPa. Microstructural characterization and failure analysis of fractured surfaces of crept samples were carried out with optical and scanning electron microscopy with EDS. Phases were identified by Rietveld refinement. The results showed that the superalloy VAT 32 has higher creep resistance than the VAT 36. The superior creep resistance of the alloy VAT 32 is related to its higher fraction of carbides (Nb,Ti)C and intermetallic L12 provided by the amount of carbon, titanium, and niobium in its chemical composition and subsequent heat treatment. During creep deformation these precipitates produce anchoring effect of grain boundaries, hindering relative slide between grains and therefore inhibiting crack formation. These volume defects act also as obstacles to dislocation slip and climb, decreasing the creep rate. Failure analysis of surface fractures of crept samples showed intergranular failure mechanism at crack origin for both alloys VAT 36 and VAT 32. Intergranular fracture involves nucleation, growth, and subsequent binding of voids. The final fractured portion showed transgranular ductile failure, with dimples of different shapes, generated by the formation and coalescence of microcavities with dissimilar shape and sizes. The occurrence of a given creep mechanism depends on the test conditions. At creep tests of VAT 32 and VAT 36, for lower stresses and higher temperature, possible dislocation climb over carbides and precipitates would prevail. For higher stresses and intermediate temperatures shear mechanisms involving stacking faults presumably occur over a wide range of experimental conditions.

A dynamic ductile failure analysis of shell structures using a nonlocal XFEM method with experimental validation

2018 ◽  
Vol 123 ◽  
pp. 1-12 ◽  
Author(s):  
C.T. Wu ◽  
N. Ma ◽  
Y. Guo ◽  
W. Hu ◽  
K. Takada ◽  
...  
Keyword(s):  
Failure Analysis ◽  
Experimental Validation ◽  
Ductile Failure ◽  
Shell Structures

scholarly journals Finite Fracture Mechanics Assessment in Moderate and Large Scale Yielding Regimes

Metals ◽  
2019 ◽  
Vol 9 (5) ◽  
pp. 602 ◽  
Author(s):  
Ali Reza Torabi ◽  
Filippo Berto ◽  
Alberto Sapora
Keyword(s):  
Fracture Toughness ◽  
Fracture Mechanics ◽  
Large Scale ◽  
Ductile Failure ◽  
Equivalent Material ◽  
Failure Initiation ◽  
Equivalent Material Concept ◽  
Finite Fracture Mechanics ◽  
Al 7075 ◽  
Scale Yielding

The coupled Finite Fracture Mechanics (FFM) criteria are applied to investigate the ductile failure initiation at blunt U-notched and V-notched plates under mode I loading conditions. The FFM approaches are based on the simultaneous fulfillment of the energy balance and a stress requirement, and they involve two material properties, namely the fracture toughness and the tensile strength. Whereas the former property is obtained directly from experiments, the latter is estimated through the Equivalent Material Concept (EMC). FFM results are presented in terms of the apparent generalized fracture toughness and compared with experimental data already published in the literature related to two different aluminium alloys, Al 7075-T6 and Al 6061-T6, respectively. It is shown that FFM predictions can be accurate even under moderate or large scale yielding regimes.

Failure Analysis enhancement by evaluating the Photoelectric Laser Stimulation impact on mixed-mode ICs

2008 ◽  
Vol 48 (8-9) ◽  
pp. 1529-1532 ◽  
Author(s):  
M. Sienkiewicz ◽  
P. Perdu ◽  
A. Firiti ◽  
K. Sanchez ◽  
O. Crepel ◽  
...  
Keyword(s):  
Failure Analysis ◽  
Mixed Mode ◽  
Laser Stimulation
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