HREM study on Sm(Co, Fe, Cu, Ti)7 alloy aged under different conditions

Liu Ansheng, Kenji Hiraga, Daisuke Shindo, Makoto Hirabayashi

Research output: Contribution to journalArticlepeer-review


The microstructures and defects of various aged Sm(Co, Fe, Cu, Ti)7 alloys have been observed in several orientations by using high resolution electron microscopy. Experimental results indicate that the alloy is composed of Sm2(Co, Fe, Cu, Ti)17(2:17) phase with a small amount of titanium and Sm(Co, Fe, Cu)5(1:5) phase. The 2:17 phase is rich in iron and the 1:5 phase is rich in copper. At aging stages corresponding to the peak magnetic coercivity, the alloy has a cellular-like microstructure with fine cells of the 2:17 phase surrounded by thin boundaries of the 1: 5 phase. The average size of the cells is about 33 nm. The orientation relationship of [0001]2:17// [0001]1:5 and (1210)2:17// (0110)1:5 has been found in this alloy. The high resolution images show coherence between 2:17 phase and 1:5 phase and very small mismatch in some phase boundaries. The cells of 2:17 phase are full of microtwins with twin plane perpendicular to c axis. The cells of 2:17 phase rapidly grow up, when the aging temperature rises and aging time prolongs. For the alloy aged at 850 °C, the 2:17 phase and 1:5 phase transform from cellular-like into strip-like microstructure, and a few of twin boundaries can be seen in the 2:17 phase. Besides the twin boundaries, antiphase boundaries are sometimes observed in the 2:17 phase of the alloy aged at 800 °C, for 10 h.

Original languageEnglish
Pages (from-to)255-256
Number of pages2
JournalJournal of Rare Earths
Issue number4
Publication statusPublished - 1996 Jan 1


  • Defects
  • High resolution electron microscopy
  • Microstructure
  • Permanent magnet
  • Sm-Co alloy

ASJC Scopus subject areas

  • Chemistry(all)
  • Geochemistry and Petrology

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