The microstructure and thermal stability of the two-component melt-spun Ni₅₅Fe₂₀Cu₅P₁₀B₁₀ TCMS amorphous/amorphous composite

The aim of this study is to present the special features and properties of the two alloys of similar average chemical composition Ni₅₅Fe₂₀Cu₅P₁₀B₁₀, processed through two different routes. The first alloy was melt-spun after the ejection of homogeneous liquid using a traditional single chamber crucible, and the second alloy was ejected from a double chamber crucible as two separate liquids: i.e., Ni₄₀Fe₄₀B₂₀ and Ni₇₀Cu₁₀P₂₀, mixing only at the orifice area. The studies of the microstructure of the composite alloy were performed through the use of transmission electron microscopy and scanning electron microscopy. The Ni₅₅Fe₂₀Cu₅P₁₀B₁₀ two-chamber melt-spun (TCMS) alloy, as well as the homogeneous Ni₅₅Fe₂₀Cu₅P₁₀B₁₀, Ni₄₀Fe₄₀B₂₀, and Ni₇₀Cu₁₀P₂₀ alloys, were heated to elevated temperatures and their characteristics studied by means of differential scanning calorimetry. The temperature resistivity change method was applied to the examination of the Ni₅₅Fe₂₀Cu₅P₁₀B₁₀ TCMS alloy. The phase composition after heat treatment was investigated using X-ray diffraction. The results of the microstructure examination show that the TCMS alloy is an amorphous/amorphous composite, and is notable for its Ni-Fe-B and Ni-Cu-P stripes resulting from its differentiated chemical composition. Another unique feature of the TCMS alloy is that it retains its wood-like morphology even after high-temperature heat treatment. The crystallisation of the TCMS alloy starts from the Ni-Cu-P constituent and ends with the Ni-Fe-B areas of the sample. The results are discussed on the basis of previous work completed on amorphous matrix composites.