Nucleation and growth of twins in Zr: A statistical study

Abstract An in-depth statistical analysis using electron backscatter diffraction (EBSD) is carried out to expose statistical correlations between { 10 1 ¯ 2 } twinning and grain size, crystallographic orientation, grain boundary length, and neighbor misorientation in high-purity polycrystalline zirconium strained to 5% and 10% at 77 K. A strong correlation was found between the active twin variant and crystallographic orientation. The propensity of a grain to twin or not was found to be only weakly dependent on grain area and diameter. Within the population of grains containing twins the number of twins per grain noticeably increases with grain area, and twin thickness is found to be rather insensitive to grain size and orientation. A weak preference for twinning was found for smaller grain boundary misorientation angles. These and the other statistical results reported can improve theoretical treatments for twin nucleation in polycrystal models. The statistical methodology presented has general applicability for all twin types in a wide range of metals.

[1]  M. Barnett.  A rationale for the strong dependence of mechanical twinning on grain size , 2008 .

[2]  Carlos N. Tomé,et al.  A dislocation-based constitutive law for pure Zr including temperature effects , 2008 .

[3]  Jian Wang,et al.  Nucleation of a (1¯012) twin in hexagonal close-packed crystals , 2009 .

[4]  W. Hosford.  The mechanics of crystals and textured polycrystals , 1993 .

[5]  Marc A. Meyers,et al.  THE ONSET OF TWINNING IN METALS: A CONSTITUTIVE DESCRIPTION , 2001 .

[6]  I. Beyerlein,et al.  Slip-assisted twin growth in hexagonal close-packed metals , 2009 .

[7]  Sean R. Agnew,et al.  Nonbasal deformation modes of HCP metals and alloys: Role of dislocation source and mobility , 2002 .

[8]  A. Serra,et al.  Dislocations in interfaces in the h.c.p. metals—I. Defects formed by absorption of crystal dislocations , 1999 .

[9]  Rodney J. McCabe,et al.  Role of twinning in the hardening response of zirconium during temperature reloads , 2006 .

[10]  Amit Misra,et al.  Quantitative analysis of deformation twinning in zirconium , 2009 .

[11]  Bjørn Clausen,et al.  Reorientation and stress relaxation due to twinning: Modeling and experimental characterization for Mg , 2008 .

[12]  J. K. Lee,et al.  Deformation twinning in h.c.p. metals and alloys , 1991 .

[13]  K. Okazaki,et al.  Effects of interstitial content and grain size on the strength of titanium at low temperatures , 1973 .

[14]  M. Barnett,et al.  Influence of grain size on the compressive deformation of wrought Mg–3Al–1Zn , 2004 .

[15]  J. Byrne,et al.  The inhibition of deformation twinning by precipitates in a magnesium-zinc alloy , 1969 .

[16]  G. Proust,et al.  Modeling texture, twinning and hardening evolution during deformation of hexagonal materials , 2007 .

[17]  S. Mendelson,et al.  Dislocation Dissociations in hcp Metals , 1970 .

[18]  A. Serra,et al.  A new model for {1012} twin growth in hcp metals , 1996 .

[19]  A. Akhtar,et al.  Plastic deformation of zirconium single crystals , 1971 .

[20]  Ricardo A. Lebensohn,et al.  Mechanical response of zirconium—I. Derivation of a polycrystal constitutive law and finite element analysis , 2001 .

[21]  I. Beyerlein,et al.  Nucleation and stability of twins in hcp metals , 2008 .

[22]  Gwénaëlle Proust,et al.  Modeling the effect of twinning and detwinning during strain-path changes of magnesium alloy AZ31 , 2009 .

[23]  Amit Misra,et al.  Effects of texture, temperature and strain on the deformation modes of zirconium , 2006 .