High-plasticity free-cutting zinc alloy

A free-cutting zinc alloy comprising the following components in percentage of weight:

• 2-7% Cu, 0.1-1.2% Bi, 0.1-0.4% Mn, 0.01-0.3% Ti, and 0.01-0.02% Zr, optional component X, optional component Y, and a remainder component being Zn having less than or equal to 0.01% unavoidable impurities,
• wherein component X amounts to 0-1.0% and comprises at least one element selected from Cr, V, Nb, Ni and Co;
• and component Y amounts to 0-1.0% and comprises at least one element selected from B, As, P and rare earth metal,
• wherein the zinc alloy has phases in an as-cast structure, and further comprises a matrix phase Zn and phases distributed in the matrix phase Zn including a plurality of Zn—Cu compounds, a plurality of herringbone intermetallic compounds, and free spherical Bi particles, the herringbone intermetallic compounds are mainly Zn—Mn—Cu—Ti compound and/or Zn—Mn—Cu—Zr compound with the remainder being Zn—Cu—Ti compound and/or Zn—Cu—Zr compound.