Mechanical Properties and Thermal Stability of (Fe, Co, Ni)-M-B (M=IV, V and VI Group Transition Metals) Amorphous Alloys with Low Boron Concentration

New type amorphous alloys, whose compositions do not belong to the previous categories, have been found in wide composition ranges of iron, cobalt or nickel-IV, V or VI group transition metal-boron ternary alloys containing less than 10 at% B by a melt spinning technique. Vickers hardness (H_v) and crystallization temperature (T_x) of these amorphous alloys increase definitely with the amount of the transition metal (M) or boron element. The H_v and T_x values are highest for the alloys containing hafnium followed by zirconium, tantalum, titanium and then niobium. Only when the H_v and T_x values are plotted as a function of the difference of electronegativity between the base metal (Fe, Co or Ni) and M or the metalloid (B) and M, it has been found that there exists an apparent linear relationship and the larger the difference in electronegativity, the higher is the H_v and T_x. It is therefore inferred that a strong chemical interaction between the base metal and M or boron and M plays an important role in the H_v and T_x of the amorphous alloys