TY - JOUR
T1 - Liquid metal embrittlement of advanced high strength steel
T2 - Experiments and damage modeling
AU - Prabitz, Konstantin Manuel
AU - Asadzadeh, Mohammad Z.
AU - Pichler, Marlies
AU - Antretter, Thomas
AU - Beal, Coline
AU - Schubert, Holger
AU - Hilpert, Benjamin
AU - Gruber, Martin
AU - Sierlinger, Robert
AU - Ecker, Werner
N1 - Funding Information:
Funding:TheauthorsgratefullyacknowledgethefinancialsupportunderthescopeoftheCOMET program within the K2 Center “Integrated Computational Material, Process and Product Engineering (IC-MPPE)” (project number 859480). This program is supported by the Austrian FederalMinistriesforClimateAction,Environment,Energy,Mobility,InnovationandTechnology (BMK)andforDigitalandEconomicAffairs(BMDW),representedbytheAustrianresearchfunding association(FFG)andthefederalstatesofStyria,UpperAustriaandTyrol.
Funding Information:
The authors gratefully acknowledge the financial support under the scope of the COMET program within the K2 Center ?Integrated Computational Material, Process and Product Engineering (IC-MPPE)? (project number 859480). This program is supported by the Austrian Federal Ministries for Climate Action, Environment, Energy, Mobility, Innovation and Technology (BMK) and for Digital and Economic Affairs (BMDW), represented by the Austrian research funding association (FFG) and the federal states of Styria, Upper Austria and Tyrol.
Publisher Copyright:
© 2021 by the authors. Licensee MDPI, Basel, Switzerland.
PY - 2021/9/1
Y1 - 2021/9/1
N2 - In the automotive industry, corrosion protected galvanized advanced high strength steels with high ductility (AHSS-HD) gain importance due to their good formability and their lightweight potential. Unfortunately, under specific thermomechanical loading conditions such as during resistance spot welding galvanized, AHSS-HD sheets tend to show liquid metal embrittlement (LME). LME is an intergranular decohesion phenomenon leading to a drastic loss of ductility of up to 95%. The occurrence of LME for a given galvanized material mainly depends on thermal and mechanical loading. These influences are investigated for a dual phase steel with an ultimate tensile strength of 1200 MPa, a fracture strain of 14% and high ductility (DP1200HD) by means of systematic isothermal hot tensile testing on a Gleeble® 3800 thermomechanical simulator. Based on the experimental findings, a machine learning procedure using symbolic regression is applied to calibrate an LME damage model that accounts for the governing quantities of temperature, plastic strain and strain rate. The finite element (FE) implementation of the damage model is validated based on the local damage distribution in the hot tensile tested samples and in an exemplary 2-sheet resistance spot weld. The developed LME damage model predicts the local position and the local intensity of liquid metal induced cracking in both cases very well.
AB - In the automotive industry, corrosion protected galvanized advanced high strength steels with high ductility (AHSS-HD) gain importance due to their good formability and their lightweight potential. Unfortunately, under specific thermomechanical loading conditions such as during resistance spot welding galvanized, AHSS-HD sheets tend to show liquid metal embrittlement (LME). LME is an intergranular decohesion phenomenon leading to a drastic loss of ductility of up to 95%. The occurrence of LME for a given galvanized material mainly depends on thermal and mechanical loading. These influences are investigated for a dual phase steel with an ultimate tensile strength of 1200 MPa, a fracture strain of 14% and high ductility (DP1200HD) by means of systematic isothermal hot tensile testing on a Gleeble® 3800 thermomechanical simulator. Based on the experimental findings, a machine learning procedure using symbolic regression is applied to calibrate an LME damage model that accounts for the governing quantities of temperature, plastic strain and strain rate. The finite element (FE) implementation of the damage model is validated based on the local damage distribution in the hot tensile tested samples and in an exemplary 2-sheet resistance spot weld. The developed LME damage model predicts the local position and the local intensity of liquid metal induced cracking in both cases very well.
KW - Advanced high strength steel
KW - Damage modeling
KW - Finite element modeling
KW - Genetic programming
KW - Liquid metal embrittlement
KW - Machine learning
KW - Resistance spot welding
KW - Symbolic regression
UR - http://www.scopus.com/inward/record.url?scp=85115655638&partnerID=8YFLogxK
U2 - 10.3390/ma14185451
DO - 10.3390/ma14185451
M3 - Article
AN - SCOPUS:85115655638
SN - 1996-1944
VL - 14
JO - Materials
JF - Materials
IS - 18
M1 - 5451
ER -