Hot-dip galvanized steel sheet and manufacturing method thereof

A hot-dip galvanized steel sheet comprising:

• a steel sheet;
• and
• a plated layer on a surface of the steel sheet,
• wherein the steel sheet contains, by mass %,
• C:
• equal to or more than 0.05% and less than 0.40%,
• Si:
• 0.5% to 3.0%,
• Mn:
• 1.5% to 3.0%,
• O:
• limited to 0.006% or less,
• P:
• limited to 0.04% or less,
• S:
• limited to 0.01% or less,
• Al:
• limited to 2.0% or less,
• N:
• limited to 0.01% or less, and
• the remainder including Fe and unavoidable impurities,
• wherein a microstructure of the steel sheet contains,
• by volume fraction, equal to or more than 20% and equal to or less than 99% in total of one or two of a martensite and a bainite, and
• a residual structure including a ferrite, and one or two of a residual austenite of less than 8% by volume fraction, and a pearlite of equal to or less than 10% by volume fraction,
• wherein a tensile strength of the steel sheet is equal to or greater than 980 MPa,
• wherein the plated layer is a galvannealed layer which contains oxides including one or two or more of Si, Mn, and Al, contains equal to or more than 7 mass % and equal to or less than 15 mass % of Fe, and the remainder including Zn, Al, and unavoidable impurities, and
• wherein when a cross section including the steel sheet and the galvannealed layer is seen in a sheet thickness direction, a projected area ratio which is an area ratio obtained by dividing a length of the oxides projected to an interface between the galvannealed layer and the steel sheet by a length of the interface between the galvannealed layer and the steel sheet, is equal to or more than 10% and equal to or less than 90%.