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Zn38Mg 12Ca32Yb 18 bulk metallic glass(BMG)presents higher corrosion resistance,lower glass transition temperature and lower density than most BMGs.Dynamic mechanical properties of Zn38Mg12Ca32Yb18 BMG were investigated by mechanical spectroscopy.The α process in the isothermal spectra can be described by a Kohlrausch-Williams-Watts(KWW)function with KWW=0.505.At high frequency,an extra contribution to the process(i.e.an excess wing)is observed with a much slower frequency dependence,the loss dynamic shear modulus G"(f)~f-0.37,which implies that the presence of a submerged secondary peak.The temperature dependence of the relaxation time is found to be very strong.We find that for this BMG the correlation between fragility and KWW fails and thus not general for BMGs.