Effects of High Co Contents in Fe-Cr-Mo-C-B-Y Alloy on the Glass Forming and the Mechanical Properties

A series of wedge shape Fe24+XCo24-XCr15Mo14C15B6Y2 (x=0,2,4,6,8) samples were prepared by copper mold suction casting method. The effects of high Co contents on glass forming ability (GFA) and mechanical properties of Fe24+XCo24-X Cr15Mo14C15B6Y2 bulk metallic glasses (BMG) were investigated, respectively. The glass forming ability of bulk amorphous Fe24+XCo24-XCr15Mo14C15B6Y2 (x=0,2,4,6,8) and Fe41Co7Cr15Mo14C15B6Y2 alloys have been researched. Simultaneously, the thermal conductivity parameters of those alloys were tested. The maximum thickness of amorphous region of wedge-shaped samples are dm =7.80 mm for Fe28Co20Cr15Mo14C15B6Y2, dm =7.10 mm for Fe41Co7Cr15Mo14C15B6Y2 and the thermal conductivity are λ=7.11 w.m-1.k-1 and 7.19 w.m-1.k-1, the thermal diffusivity are α=1.875 mm2/s and 1.905 mm2/s for Fe28Co20Cr15Mo14C15B6Y2 and Fe41Co7Cr15Mo14C15B6Y2 BMGs, respectively. The glass forming ability of Fe28Co20Cr15Mo14C15B6Y2 alloy is bigger than that of well known Fe41Co7Cr15Mo14C15B6Y2 alloy. With the change of Co content, the Vickers hardness of Fe24+XCo24-XCr15Mo14C15B6Y2 (x=0,2,4,6,8) change from 1292 to 1322Hv.