Glidcop


Glidcop is a family of copper-based metal matrix composite alloys mixed primarily with small amounts of aluminum oxide ceramic particles. It is a trademark of North American Höganäs. The name is sometimes written GlidCop or GLIDCOP.
The aluminum oxide particles block dislocation creep, which retards recrystallization and prevents grain growth; thus preserving the metal's strength at high temperatures. They also protect the metal against radiation damage. On the other hand, they exclude the possibly of heat treatment or hot working of the worked parts.

Properties

Composition and physical properties

Glidcop is available in several grades which have varying amounts of aluminum oxide content.
GradeAluminum oxide
content		UNS alloy numberMelting pointDensityElectrical
conductivity		Thermal
conductivity		Coefficient of thermal expansion
Modulus of
elasticity
OFC0%-8.94 g/cm3
58 MS/m
391 W/m·K
17.7 µm/m·K
115 GPa
Glidcop AL-150.3 wt. %UNS-C157158.90 g/cm3
54 MS/m
365 W/m·K
16.6 µm/m·K
130 GPa
Glidcop AL-250.5 wt. %UNS-C157258.86 g/cm3
50 MS/m
344 W/m·K
16.6 µm/m·K
130 GPa
Glidcop AL-601.1 wt. %UNS-C157608.81 g/cm3
45 MS/m
322 W/m·K
16.6 µm/m·K
130 GPa

Additional materials and elements can be added if lower thermal expansion is required, or higher room temperature and elevated temperature strengths. The hardness can also be increased. A composite material of Glidcop AL-60 and 10% Niobium provides high strength and high conductivity. The hardness is comparable to many copper-beryllium and copper-tungsten alloys, while the electrical conductivity is comparable to RWMA Class 2 alloy. Other additives for specialized applications include molybdenum, tungsten, Kovar, and Alloy 42.
t Glidcop AL-15 has a yield strength of over 29 ksi.

Post-neutron-irradiation properties

Glidcop is resistant to degradation by neutron irradiation. Samples irradiated by neutrons at and cooled to room temperature were found to have greater tensile strength and electrical conductivity and less swelling than samples of pure copper under the same treatment. For radiation levels of 0 to 150 dpm, the tensile strength was nearly constant and swelling not noticeable, while pure copper experienced a linear decrease in tensile strength and 30% swelling between 0 and 50 dpm. While both pure copper and Glidcop experienced linear drops of electrical conductivity, the drop for Gildcop was smaller.

Workability

The machinability and cold working properties of Glidcop are similar to those of pure copper. Brazing with silver-based brazing alloys may require first electroplating the Glidcop part with either copper or nickel. The copper plating can be done with a copper cyanide solution; other solutions may not work. Gold-based brazing alloys like 3565 AuCu and 5050 AuCu, can be used in a dry hydrogen atmosphere.
Cold working Gildcop by drawing, cold heading etc. increases its strength through work hardening while reducing ductility.

Applications

Glidcop uses include resistance welding electrodes to prevent them from sticking to galvanized and other coated steels. It has also been used in applications where its resistance to softening at high temperatures is necessary, including incandescent light bulb, leads relay blades, contactor supports, x-ray tube components, heat exchanger sections for fusion power and synchrotron units, high field magnetic coils, sliding electrical contacts, arc welder electrodes, electronic leadframes, MIG contact tips, commutators, high speed motor and generator components, and microwave power tube components.
Glidcop has also been used in hybrid circuit packages due to its compatibility with high temperature brazing, and in particle accelerator components, such as radio frequency quadrupoles and compact X-ray absorbers for undulator beam lines, where the alloy may be subjected to high temperatures and high radiation simultaneously.