Method of manufacturing composite structures

A method of manufacturing a composite structure made from a pair of materials of different types mechanically joined to each other, said method comprising the steps of:

• providing a first material having a planar first joining surface;
• providing a second material softer than said first material and having a second joining surface;
• rolling and pressing on said first joining surface a formation roll having flat opposite side surfaces and a tapered peripheral surface defining a circumferential ridge of V-shaped cross section, thereby forming in said first joining surface a groove of a substantially V-shaped cross section having an upright side wall and an opposite sloping side wall defining a valley portion of said groove, and simultaneously forming a raised portion on said first joining surface along said upright side wall of the groove due to plastic flow of said first material adjacent said groove as said formation roll is pressed to form said groove;
• then rolling and pressing a cylindrical formation roll on said first joining surface to plastically deform said raised portion inwardly of said groove, to thereby make said first joining surface planar and to form said upright side wall into an overhang side wall, thus forming a completed overhang groove;
• opposing said first and second joining surfaces of said first and second materials;
• and
• pressing said first and second materials against each other to cause forced plastic flow of said softer second material into said overhang groove in the first material in a manner fully filling said overhang groove, thereby obtaining firm engagement between said first and second materials.

A method of manufacturing a composite structure made from a pair of materials of different types mechanically joined to each other, said comprising the steps of:

• providing a first material having a planar first joining surface;
• providing a second material softer than said first material and having a second joining surface;
• rolling and pressing on said first joining surface a pulley-type formation roll having flat opposite side surfaces and a peripheral surface with a circumferential groove of a V-shaped cross section, thereby forming in said first joining surface a groove having parallel side walls and a bottom ridge, and simultaneously forming raised portions on said first joining surface along opposite longitudinal sides of said groove due to plastic flow of said first material adjacent said groove as said formation roll is pressed to form said groove;
• then rolling and pressing on said first joining surface a cylindrical formation roll to plastically deform said raised portions inwardly of said groove in said first joining surface, to thereby form said side walls of said groove into overhang side walls and to form a completed overhang groove;
• opposing said first and second joining surfaces of said first and second materials;
• and
• pressing said first and second materials against each other to cause forced plastic flow of said softer second material into said overhang groove in said first material in a manner fully filling said overhang groove, thereby obtaining firm engagement between said first and second materials.

A method of forming grooves having overhang side walls in an outer surface of a metal member, said method comprising the steps of:

• rolling and pressing on said outer surface a first formation roll having radially protruding parallel annular roll portions of a substantially rectangular cross-sectional shape, thereby forming in said outer surface parallel grooves each having parallel side walls, and substantially forming raised portions on said outer surface along opposite longitudinal sides of each of said grooves due to plastic flow of said metal member adjacent each said groove as said annular roll portions are pressed to form the respective grooves;
• then rolling and pressing on said outer surface a second formation roll having parallel circumferential grooves of a substantially triangular cross-sectional shape, with respective said circumferential grooves coinciding in position with respective said grooves in said outer surface, to thereby plastically deform said raised portions inwardly of each groove in said outer surface to thereby form the side walls of each groove into overhang side walls;
• and
• thereafter rolling and pressing a third formation roll of cylindrical configuration on said outer surface to make it planar.