Non-Isothermal Crystallization Behavior of a Zr-Based Amorphous Alloy Composite Prepared by Selective Laser Melting.

ZrCuAlCo bulk amorphous alloy composites were prepared by selective laser melting (SLM) technology under different processing conditions and their non-isothermal crystallization behaviors were systematically investigated. The results show that the crystallization phases are CuZr and CuZr for both gas-atomized powder and SLMed samples. The dependence of volume fraction of CuZr and CuZr on laser energy density can be fitted by an exponential function. The crystalline sizes of CuZr and CuZr linearly increase with increasing energy density. The thermal stability is larger for the gas-atomized powders than for the SLMed bulk samples. It is interestingly found that there is an exponential relationship between the crystallization enthalpy Δ and the amorphous content. In addition, the glass transition is more difficult for the gas-atomized powders than for the SLMed bulk samples. The crystallization procedure is more difficult for the SLMed bulk samples than for the gas-atomized powders. The local activation energy decreases with increasing α for the gas-atomized powder and the SLMed bulk samples. In addition, the is larger for the SLMed bulk samples than for the gas-atomized powder at the corresponding crystallization fraction α. The dependence of the local Avrami exponent n(α) on the α is similar for both the gas-atomized powders and the SLMed bulk samples at studied heating rates. The crystallization mechanism is also discussed.