Onset of fracture in high pressure die casting aluminum alloys

Abstract This paper deals with the development of a phenomenological criterion for the prediction of crack initiation in engineering structures made of the pressure die casting alloy Al–10Si–Mg–Mn. A custom-made biaxial testing device is employed to load a newly-designed flat specimen under various combinations of shear and normal loading. In a hybrid experimental–numerical approach, the crack initiation could be studied for stress triaxialities ranging from about 0.0 to 0.6. A phenomenological fracture criterion has been calibrated which predicts the onset of fracture based on the stress triaxiality and the maximum principal strain. The results from post-mortem metallographic analysis suggest that fracture of Si-particles leads to the macroscopic crack formation at stress triaxialities above 0.25, whereas Al-matrix instability failure along with particle–matrix delamination seems to initiate macroscopic cracks at stress triaxialities around 0.0.

[1]  R. Doglione,et al.  Secondary foundry alloy damage and particle fracture , 2003 .

[2]  T. Antretter,et al.  Particle cleavage and ductile crack growth in a two-phase composite on a microscale , 1998 .

[3]  J. R. Griffiths,et al.  The deformation and fracture behaviour of an AlSiMg casting alloy , 1995 .

[4]  Yingbin Bao,et al.  Prediction of ductile crack formation in uncracked bodies , 2003 .

[5]  J. Hancock,et al.  On the mechanisms of ductile failure in high-strength steels subjected to multi-axial stress-states , 1976 .

[6]  F. A. McClintock,et al.  A Criterion for Ductile Fracture by the Growth of Holes , 1968 .

[7]  W. Dahl,et al.  Investigations concerning quantitative determination of local damage in ductile materials , 1992 .

[8]  D. M. Tracey,et al.  On the ductile enlargement of voids in triaxial stress fields , 1969 .

[9]  J. Yeh,et al.  The cracking mechanism of silicon particles in an A357 aluminum alloy , 1996 .

[10]  P. Steinmann,et al.  RVE-based studies on the coupled effects of void size and void shape on yield behavior and void growth at micron scales , 2006 .

[11]  J. Arndt,et al.  Effects of the constraint parameter triaxial stress on the failure behaviour of steels , 1993 .

[12]  A. Gurson.  Continuum Theory of Ductile Rupture by Void Nucleation and Growth: Part I—Yield Criteria and Flow Rules for Porous Ductile Media , 1977 .

[13]  A. Ghilarducci,et al.  Fracture behaviour of an Al–Mg–Si industrial alloy , 2001 .

[14]  A. Öchsner,et al.  Experimental and numerical investigations of ductile damage in aluminium alloys , 2001 .

[15]  Leon Mishnaevsky,et al.  In-situ observation of damage evolution and fracture in AlSi7Mg0.3 cast alloys , 1999 .

[16]  A. Needleman,et al.  Analysis of the cup-cone fracture in a round tensile bar , 1984 .

[17]  X. Niu,et al.  Vacuum assisted high pressure die casting of aluminium alloys , 2000 .

[18]  T. Wierzbicki,et al.  On fracture locus in the equivalent strain and stress triaxiality space , 2004 .

[19]  G. R. Johnson,et al.  Fracture characteristics of three metals subjected to various strains, strain rates, temperatures and pressures , 1985 .

[20]  Odd Sture Hopperstad,et al.  On the influence of stress triaxiality and strain rate on the behaviour of a structural steel. Part II. Numerical study , 2003 .

[21]  Mark F. Horstemeyer,et al.  A void–crack nucleation model for ductile metals , 1999 .