The influence of the initial texture on the post ECAP deformation and recrystallization texture and r values of a A1050 aluminum

W. SUSSAI; A.M. KLIAUGA; R.E. BOLMARO; V. L SORDI; M FERRANTE

Bangalore

Conferencia; ICSMA 16; 2012

ICSMA

Rolled and recrystallized aluminum exibit strong {001} <100> cube texture, which has a high deformation anisotropy. Deformation by shear can change that texture and the resulting recrystallization texture into a more favorable orientation to further forming processes [1,2]. In this work the ECAP deformation and subsequent recrystallization of a AA1050 aluminium from two different casting processes was compared, The first sample was ECAP deformed just after continuous roll casting and the second sample was die casted and deformed by hot rolling prior to ECAP; both samples had a initial thickness of 7mm. The deformation was performed in a ECAP die with an internal angle of 120o and route A , 1 to 4 passes was applied. After deformation the samples were treated at 350oC for 1 hour. The texture of the plate center was analyzed by x –ray diffraction, the microstructural evolution was observed by optical microscopy and TEM. Tensile samples were extracted parallel, perpendicular and at 45o form the extrusion direction and the plastic strain anisotropy (r) was measured. The main differences between the samples were the initial microstructures as well as their textures (resume of the texture analysis is presented in Figure 1): the roll casting sample had a heterogeneous microstructure across the thickness: recystallized grains with mainly rotated cube texture at the surface and deformed large grains with mainly brass texture in the plate center. The hot rolled sample was more homogeneous with large deformed grains across the thickness  and presented  typical mixture of Brass/Copper /Goss components.  Only the plates center was analyzed. The rotation axis during ECAP was parallel to the transverse axis of the previous rolling direction. For the strong brass component sample the final texture after 4 passes consisted of a strong {111} // TD component.  This orientation did not change after treating at 350oC for 1 hour. The ecaped hot rolled sample presented a continuous reduction of texture intensity from 1 to 4 passes with the strongest components being {111}<112> and {111}<110> but also presented rotated cube component at the deformed condition. The texture after heat treatment was very low (2 times random).  The strong texture of the roll casting sample lead to a higher plastic anisotropy when compared with the weakly textured. [1] J. Sidor, A. Miroux, R. Petrov, L. Kestens, Acta Materialia 56 (2008), p.2495 [2]. H.Jin, DJ Lloyd: Mat. Sci.. Eng. A A399 (2005), p. 358