To obtain excellent magnetic properties of machinable REPM prepared by directional solidification (DS) technology, Space A, a composition area with theta=0 degrees similar to 5 degrees where easy axis is parallel to s...To obtain excellent magnetic properties of machinable REPM prepared by directional solidification (DS) technology, Space A, a composition area with theta=0 degrees similar to 5 degrees where easy axis is parallel to solidified direction of alloys, has been established in Zr-Sm-La-Co-Cu-Fe system. In 2/17+1/5+Co, and 2/17+1/5 region near Co phase of Space A, one obtains: V-f = 80.933 - 2.739Zr - 1.828Sm - 0.773Co - 0.147Cu + 0.415Fe + 0.218La Nonequilibrium solidification process of alloys in 2/17+1/5+Co region, is as follows: L-->Co, L-->2/17, L+2/17-->1/5 and L-->1/(5-x)+1/(5+x). The product of partially completed peritectic reaction, and 1/(5-x) and 1/(5+x) phases can all be transformed into a homogeneous 1/5 phase after solution treatment in 1413 K for 5 h. Containing 3 similar to 6% Co phase magnetically hardened by 0.5 similar to 2.5% V, the DS magnets have been achieved with both improved toughness and excellent coercive force of 520 kA/m.展开更多
The main features of morphology evolution of crystal growth during near rapid directional solidification were reviewed and the concept of effective constitutional supercooling was proposed. On the basis of interface s...The main features of morphology evolution of crystal growth during near rapid directional solidification were reviewed and the concept of effective constitutional supercooling was proposed. On the basis of interface stability theory combined with experiments, the behaviour of transition from dendrites to fine cells was quantitatively described, and the transition from cells to plane front of absolute stability was also examined.展开更多
文摘To obtain excellent magnetic properties of machinable REPM prepared by directional solidification (DS) technology, Space A, a composition area with theta=0 degrees similar to 5 degrees where easy axis is parallel to solidified direction of alloys, has been established in Zr-Sm-La-Co-Cu-Fe system. In 2/17+1/5+Co, and 2/17+1/5 region near Co phase of Space A, one obtains: V-f = 80.933 - 2.739Zr - 1.828Sm - 0.773Co - 0.147Cu + 0.415Fe + 0.218La Nonequilibrium solidification process of alloys in 2/17+1/5+Co region, is as follows: L-->Co, L-->2/17, L+2/17-->1/5 and L-->1/(5-x)+1/(5+x). The product of partially completed peritectic reaction, and 1/(5-x) and 1/(5+x) phases can all be transformed into a homogeneous 1/5 phase after solution treatment in 1413 K for 5 h. Containing 3 similar to 6% Co phase magnetically hardened by 0.5 similar to 2.5% V, the DS magnets have been achieved with both improved toughness and excellent coercive force of 520 kA/m.
文摘The main features of morphology evolution of crystal growth during near rapid directional solidification were reviewed and the concept of effective constitutional supercooling was proposed. On the basis of interface stability theory combined with experiments, the behaviour of transition from dendrites to fine cells was quantitatively described, and the transition from cells to plane front of absolute stability was also examined.
