A
copper and
aluminium composite variable
diameter metal heat pipe structurally comprises a heat absorption section, a
butt joint section and a condensation section. A
pipe shell of the
metal heat pipe is composed of a
copper and
aluminium composite
metal pipe. The
copper and
aluminium composite metal
pipe is of an outside aluminium and inside copper structure. The heat suction section is composed of an opening sealing
welding spot (1), a
cold welding opening sealing section (2), a heat suction section outer layer (3), a heat suction section inner layer (4), a heat suction section flaring part (6) and the like. The
butt joint section is composed of
butt joint pipes (7), the butt joint pipes (7) are made of red copper or
oxygen-free copper pipes, the inner
diameter of the butt joint pipes is equal to the inner
diameter of the heat suction section inner layer (4), and the outer diameter of the butt joint pipes is equal to the inner diameter of the heat suction section flaring part (6). The condensation section is composed of a
necking-down section (8), a condensation section body (9) and the like. The size specification of the
necking-down section (8) is basically the same as that of the heat suction section flaring opening (6). A cavity of the heat suction section, a cavity of the butt joint section and a cavity of the condensation section are connected to together form a
heat pipe vacuum cavity (5), heat pipe
phase inversion hot working media (10) are arranged in the heat pipe vacuum cavity (5), and the total size of the heat pipe
phase inversion hot working media (10) is 0.1%-20% of the size of the heat pipe vacuum cavity (5). According to the copper and aluminium composite variable diameter metal heat pipe, under the condition that the strength and the reliability needed by the metal heat pipe are guaranteed, the manufacturing cost of the metal heat pipe is lowered.