Английский язык для инженеров сварочного производства. Гричин С.В - 77 стр.

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lead to a degradation of corrosion resistance since electrochemical cells are

set up between solute-rich and poor domains.

Friction Stir Welding of Cast Aluminium Alloy

The most popular aluminium casting-alloy contains about 8 wt% of

silicon. It therefore solidifies to primary aluminium-rich dendrites and a

eutectic mixture of aluminium solid-solution and almost pure silicon. The

latter occurs as coarse silicon particles which tend to be brittle. The cast alloy

usually has some porosity. Friction stir welding has the advantage that it

breaks up the coarse silicon particles and heals any pores by the mechanical

processing, as illustrated below.

Fig. 17 A section through a friction stir weld made in an Al-Si casting alloy.

There are pores indicated in the base metal (BM). HAZ represents the

heat affected zone, TMAZ – the thermomechanically affected zone, and SN –

the stir nugget. The photographs in this section have kindly been provided by

Professor H. Fujii of JWRI, Japan.