J Mater Sci Technol ›› 1997, Vol. 13 ›› Issue (6): 475-478.

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Machinable REPM with Excellent Intrinsic Coercive Force Prepared by DS Technology

Xincai LIU; Jin PAN; Zhifeng XU ; Jianping ZHUANG; Min LIU and Dongming YU (Nanchang Institute of Aeronautical Technology, Nanchang 330034, China)Zhengxing SH and Hengzhi FU(Northwestern Polytechnic University, Xi'an 710072, China)   

  • Received:1997-11-28 Revised:1997-11-28 Online:1997-11-28 Published:2009-10-10

Abstract: To obtain excellent magnetic properties of machinable REPM prepared by directional solidification (DS) technology Space A, a composition area with θ=0°~5° 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:Vf = 80.933 - 2.739Zr - 1.828Sm - 0.773Co - 0.147Cu + 0.415Fe + 0.218LaNonequilibrium 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 3~6% Co phase magnetically hardened by 0.5~2.5% V, the DS magnets have been achieved with both improved toughness and excellent coercive force of 520 kA/m.