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The influences of Si and Al on the microstructure of Ti-containing C-Mn steels have been studied. Although Si addition up to 1 wt pct did not change the crystal structure of dominant Ti 2 O 3 particles dispersed in these steels, the formation of an acicular ferrite microstructure was suppressed at high Si contents. It has been found that the Mn content dissolved in Ti 2 O 3 particles decreases with increasing Si content. This seems to weaken the formation of Mn-depleted zones (MDZs) around Ti 2 O 3 particles, which act as a dominant driving force for the intragranular nucleation of acicular ferrite. It has also been found that the addition of a small amount of Al greatly reduces the formation of acicular ferrite. This is attributed to the change of dominant oxide particles from Ti 2 O 3 , which serves as an effective nucleant for acicular ferrite, to inert Al 2 O 3 . The result of the present study implies that it is advantageous to keep Si and Al contents in Ti-containing steels as low as possible when well-developed microstructures of acicular ferrite are desired.

Silver electrodeposits have been studied since the late 1800s and are being widely used for electrical contact materials as well as decorating purposes because of their high electrical conductivity and lower cost than gold. 1 The textures of silver electrodeposits have been reported since the 1920s. Bozorth 2 reported that 30 m thick silver electrodeposits obtained from alkaline cyanide baths with a cathode current density of 5 A/dm 2 at ambient temperature showed no preferred orientation. Finch et al. 3 found that the texture of silver electrodeposits varied with electrolytic condition and reported that <111> and <100> textures were obtained from low and high current densities, respectively. Kristev and Velinov 4,5 examined the structure of silver electrodeposits using the pole figure measurement and electron diffraction method. They found that the <111> fiber texture with its twin component, <115> T , developed most intensively over the experimental range and the <100> fiber texture developed when mercaptobenzothiazole was added as a brightener.Most recently, Kristev and Nikolova 6 examined the texture evolution in various electrolytes available for silver plating. They reported that <111> fiber component was the major in textures of silver electrodeposits, which was consistent with previously reported results. From these reports, it can be concluded that <111> fiber texture develops in silver electrodeposits obtained from most electrolytes including a cyanide one. It was also reported that other weak textures such as <110>, <100>, and <112> developed in silver electrodeposits. 7 Kristev et al. 4 explained that <113> component resulted from the superposition of <115> T and <111> orientations. But the angular difference of the two orientations is too large to make a peak near <113> by superposition of them. The evolution mechanisms of textures in deposits have been suggested by many authors. 2,3,8-12 But no satisfactory explanation has been found on textures of silver electrodeposits obtained from cyanide baths.Using hardness measurements, Raub 13 investigated the recrystallization behavior of silver electrodeposits obtained from cyanide baths, but did not study texture changes during annealing. One of the present authors 14 advanced a model for the evolution of recrystallization textures in which the direction of absolute maximum internal stress due to dislocations generated during fabrication becomes parallel to the minimum Young's modulus direction in recrystallization grains, whereby the strain energy release during recrystallization can be maximized (see the Discussion section). This model could explain the evolution of recrystallization textures from plastically deformed metals 15-21 as well as copper electrodeposits. 22,23 In this study, various textures of silver electrodeposits were obtained from cyanide baths of conventional compositions without additive and their recrystallization textures are discussed based on the model. Experimental Two different cyanide baths, high and low concentration baths, w...

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