44 research outputs found
Influence of melt feeding scheme and casting parameters during direct-chill casting on microstructure of an AA7050 billet
© The Minerals, Metals & Materials Society and ASM International 2012Direct-chill (DC) casting billets of an AA7050 alloy produced with different melt feeding schemes and casting speeds were examined in order to reveal the effect of these factors on the evolution of microstructure. Experimental results show that grain size is strongly influenced by the casting speed. In addition, the distribution of grain sizes across the billet diameter is mostly determined by melt feeding scheme. Grains tend to coarsen towards the center of a billet cast with the semi-horizontal melt feeding, while upon vertical melt feeding the minimum grain size was observed in the center of the billet. Computer simulations were preformed to reveal sump profiles and flow patterns during casting under different melt feeding schemes and casting speeds. The results show that solidification front and velocity distribution of the melt in the liquid and slurry zones are very different under different melt feeding scheme. The final grain structure and the grain size distribution in a DC casting billet is a result of a combination of fragmentation effects in the slurry zone and the cooling rate in the solidification range
Measurement of the vector and tensor analyzing powers for dp- elastic scattering at 880 MeV
The vector Ay and tensor analyzing powers Ayy and Axx for dp- elastic
scattering were measured at Td = 880 MeV over the c.m. angular range from 60 to
140 degrees at the JINR Nuclotron. The data are compared with predictions of
different theoretical models based on the use of nucleon-nucleon forces only.
The observed discrepancies of the measured analyzing powers from the
calculations require the consideration of additional mechanisms.Comment: 5 pages,3 figure