Feasibility of joining AZ31B magnesium metal matrix composite by friction welding

In this study, metal particles were added during the spot friction welding (SFW) process, a solid state sheet metal joining process, to create a localized metal matrix composite (MMC) for the improvement of lap shear strength in AISI 6111-T4 aluminum alloy sheets. The Ancorsteel® 1000 particles were compressed between the upper and lower sheets and distributed concentrically around the tool axis perpendicular to the plate surface, which formed a localized MMC and were effective as the reinforcement particles in aluminum 6111-T4 alloy sheets. Results revealed that the MMC reinforcement improved the lap shear strength of SFW joints by about 25%. An aluminum-ferrous solid solution was formed around the steel particles along the aluminum matrix interface. The load-deflection curve shows that the steel particle MMC increased both the strength and ductility of SFW joint. This is attributed to two phenomena observed on the failed lap shear tensile specimens with SFW MMC. One is the longer and more torturous crack path, and the other is the secondary crack on steel particle MMC reinforced SFW joints.

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Spot Friction Welding Joint Strength Improvement Using Localized Metal Matrix Composite Formation

ASME 2009 International Manufacturing Science and Engineering Conference, Volume 2 ◽

10.1115/msec2009-84126 ◽

2009 ◽

Cited By ~ 1

Author(s):

Senthil G. Arul ◽

Grant H. Kruger ◽

Scott F. Miller ◽

Tsung-Yu Pan ◽

Albert J. Shih

Keyword(s):

Shear Strength ◽

Metal Matrix Composite ◽

Matrix Composite ◽

Friction Welding ◽

Metal Matrix ◽

Joint Interface ◽

Lap Shear Strength ◽

Lap Shear ◽

Steel Particle ◽

Spot Friction Welding

This study investigates the application of metal particles in spot friction welding (SFW), a semi-solid state sheet metal joining process, to create the localized metal matrix composite (MMC) for the improvement of lap-shear strength. Ancorsteel® 1000 particles, compressed around the axial center-line of the tool between the upper and lower sheets, was demonstrated to form a localized MMC and effective as the reinforcement particles in aluminum 6111-T4 alloy sheets. Results revealed that the particle MMC in SFW increased the maximum lap-shear by 20%. In the stir-zone, steel particle sizes were significantly reduced due to breaking by mechanical action. Analysis revealed an aluminum-ferrous solid solution formation around the steel particle and aluminum matrix interfaces. In the heat-affected zone along the joint line, steel particles retained their original sizes and reinforced the joint interface. The load deflection curve and cross-section micrographs of the failed lap-shear tensile specimens indicated that, for steel particle MMC samples, the crack path was longer. This was due to a localized MMC forming along the joint interface and was identified as the primary factor responsible for the increase in SFW lap-shear strength.

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