Aluminum Company of America

Lake Region Manufacturing, Inc.

Roger C Dickenson

Que-Tsang Fang

James R Van Wert

Wendy Hodges

Jonathan Hardy

Steven A Jones

MP35N (35% Co, 35% Ni, 20% Cr, 10% Mo, by weight) wires (solid and clad) are widely used for leads in cardiac rhythm management (CRM) and neurological electrical stimulation devices. Over the typical lifetime of a CRM device, a lead wire is subjected to stress cycling imposed by the heartbeat and is expected to survive 300 million stress cycles, or more. Premature fatigue fracture of a lead is sometimes caused by surface imperfections in the wire that has been coiled into the lead. The imperfections can result in concentration of stresses at a specific location on the wire surface. A vexing type of imperfection is a tiny surface fissure that is commonly referred to as a chevron. Wire drawing processes that are commonly used to form wires for manufacturing an implantable lead inherently produce a distribution of tiny chevrons on the wire surface. According to the present invention, removing chevrons and other surface imperfections using an electropolishing process helps reduce or eliminate premature fatigue failure initiated by such surface imperfection.

Electropolishing of MP35N wire for fatigue life improvement of an implantable lead

Alloy and cast alloy product ideally suited for use as a component in a vehicle frame or subframe, i.e., body-in-white, comprising an alloy consisting of about 2.00 to 5.00 wt. % magnesium, up to approximately 0.30 wt. % silicon, approximately 0.20 to 1.60 wt. % manganese, up to approximately 1.00 wt. % iron, and between about 0.10 to 0.30 wt. %, zirconium, the balance substantially aluminum and incidental elements and impurities. The aluminum/magnesium alloy is typically solidified into ingot derived working stock by continuous casting or semi-continuous casting into a shape suitable for remelt for casting, which shape is typically an ingot billet. Excellent mechanical properties are obtained from a cast product that is not subjected to high temperature heat treating operations subsequent to casting.

Alloy for cast components

Growing community of inventors

Roanoke, VA, United States of America

Roger C Dickenson