1 Institute for Advanced Materials and Technology , University of Science and Technology Beijing , Beijing 100083 , China 2 Beijing Amorphous Energy Conservation Materials Industry Alliance , Beijing 100081 , China
1 Institute for Advanced Materials and Technology , University of Science and Technology Beijing , Beijing 100083 , China 2 Beijing Amorphous Energy Conservation Materials Industry Alliance , Beijing 100081 , China
ժҪ Morphology and distribution of precipitates in the Fe-6.5Si-0.02B alloy were characterized, and these e.ects on room-temperature compression cracks were investigated. The results showed that the precipitate in the Fe-6.5Si-0.02B alloy is Fe2B with body-centered tetragonal structure, and its nano-hardness is 15.0.GPa which is higher than that of the matrix (~.8.5.GPa). In the as-cast alloys, most of the intragranular precipitates are coarse lath-like with the length of 5�C15.��m and width of 2�C5.��m, and the precipitates formed at the grain boundaries are of about 2�C3.��m in width. After oil quenching followed by heat treatment at 1100.��C for more than 30.min, the precipitates inside grains are re.ned with a size of several hundred nanometers and the precipitates at the grain boundaries are re.ned with a size of <.1.��m. After compression test, transgranular and intergranular cracks occur in the as-cast alloys with coarse precipitates. For the quenched alloys with .ne precipitates, the number of cracks decreases signi.cantly, and no transgranular cracks happen because some cracks are blocked or the propagation direction is changed by grain boundary.
Abstract��Morphology and distribution of precipitates in the Fe-6.5Si-0.02B alloy were characterized, and these e.ects on room-temperature compression cracks were investigated. The results showed that the precipitate in the Fe-6.5Si-0.02B alloy is Fe2B with body-centered tetragonal structure, and its nano-hardness is 15.0.GPa which is higher than that of the matrix (~.8.5.GPa). In the as-cast alloys, most of the intragranular precipitates are coarse lath-like with the length of 5�C15.��m and width of 2�C5.��m, and the precipitates formed at the grain boundaries are of about 2�C3.��m in width. After oil quenching followed by heat treatment at 1100.��C for more than 30.min, the precipitates inside grains are re.ned with a size of several hundred nanometers and the precipitates at the grain boundaries are re.ned with a size of <.1.��m. After compression test, transgranular and intergranular cracks occur in the as-cast alloys with coarse precipitates. For the quenched alloys with .ne precipitates, the number of cracks decreases signi.cantly, and no transgranular cracks happen because some cracks are blocked or the propagation direction is changed by grain boundary.
Li H Z, Liu H T, Liu Z Y, et al.Characterization of microstructure,texture and magnetic properties in twin-roll casting high silicon non-oriented electrical steel[J].Materials Characterization, 2014, 88(88):1-6
[2]
Cai G, Li C, Wang B C Q.Effects of warm rolling reduction on the microstructure,texture and magnetic properties of Fe�C65 wt% Si steel[J].Journal of Materials Research, 2016, -1(12):1-11
[3]
Mo Y K, Zhang Z H, Pang H J, et al.Improved Plasticity and Cold-rolling Workability of Fe-65wt%Si Alloy by Warm-rolling with Gradually Decreasing Temperature[J].Journal of Materials Science & Technology, 2016, 32(5):477-484
[4]
Wang F H, Shang J X, Li J M, et al.The effects of boron and hydrogen on the embrittlement of polycrystalline Ni3Al[J].Intermetallics, 2000, 8(5�C6):589-593
[5]
Fu H, Zhang Z, Wu X, et al.Effects of boron on microstructure and mechanical properties of Fe-65wt.%Si alloy fabricated by directional solidification[J].Intermetallics, 2013, 35(2):67-72
[6]
Caceres C H, Svensson I L, Taylor J A.Strength-Ductility behaviour of Al-Si-Cu-Mg casting alloys in T6 temper[J].International Journal of Cast Metals Research, 2003, 15(5):531-543
[7]
Tang W, Han E H, Xu Y B, l.Effect of heat treatment on microstructure and properties of AZ80 magnesium alloy[J].Acta Metallrugica Sinica, 2005, 41(11):1199-1206
[8]
Chen G, Jin X, Zhou D, et al.Effects of boron content on boundaries precipitates in Ni base alloy GH4049 and its high temperature properties[J].Acta Metallrugica Sinica, 2005, 41(6):622-626
[9]
Lei L M, Huang X, Wu X R, et al.Effects of second phases on tensile fracture behavior of Ti-25V-15Cr-2Al-02C-x (x =0,2 %Mo,2 %Nb,0 .2 %Si) alloys[J].Rare Metals, 2004, 28(1):47-49
[10]
Fu H, Yang Q, Zhang Z, et al.Effects of precipitates and order degree on bending properties of an Fe-65 wt%Si alloy with columnar grains[J].Journal of Materials Research, 2011, 26(14):1711-1718
[11]
Zhang Z, Wang W, Fu H, et al.Effect of quench cooling rate on residual stress,microstructure and mechanical property of an Fe�C65Si alloy[J].Materials Science & Engineering A, 2011, 530(11):519-524
[12]
Yong Q L.Second Phases in Structural Steels. Beijing: Metallurgical Industry Press, 2006: 126.
[13]
Zheng K Y, Dong J, Zeng X Q, et al.Effect of precipitation aging on the fracture behavior of Mg�C11Gd�C2Nd�C04Zr cast alloy[J].Materials Characterization, 2008, 59(7):857-862
[14]
Xie J X.Development of compact processes for high efficiency fabrication of hard-to-working metals[J].Materials China, 2012, 29(11):1-7
2018, Vol. 25 
