EN Division-Metallurgy and Metrology Domaine / Field: LHC –11T DS Dipole Project Date: 8-5-2012 N° EDMS EDMS Nr.: 1216580 Requérant / Customer: D. Smekens (TE/MSC) Liste de distribution / Distribution list: M. Karppinen (TE/MSC) S. Sgobba (EN/MME) Characterization of DISCUP C3/30 ODS Copper from Luvata OY/ECKA Granules for 11T DS Dipole project Données expérimentales / Experimental data: Samples : 2 x 600 mm long samples Optical microscope: Microscope Digital KEYENCE; Quantimet Leica Q600 Hardness :Wolpert hardness machine Tensile tests: UTS tensile test machine SEM observations: ZEISS Sigma Dimensional metrology: Digital level TESA EN Division-Materials and Metrology CERN/EN/MME-MM/NJ-EDMS1216580

Sample description and tests performed Two extruded and drawn shapes of approximately 600 mm long made of DISCUP C3/30 from Luvata OY/ECKA Granules have been characterized through different techniques: Dimensional metrology Optical and SEM observations Hardness measurements Tensile tests The term “as received” (AR) refers to the shape prior to any heat treatment and “heat treated” (HT) following a Nb3Sn reaction type heat treatment (665 °C 50h) a b View of the 2 shapes in the “as received” state EN Division-Materials and Metrology CERN/EN/MME-MM/NJ-EDMS1216580

Macro observations Face Face A R30.1 Cross section in comparison with the plane provided (LHCMBHSP0023) Presence of some stain on the surface in the “As received” state EN Division-Materials and Metrology CERN/EN/MME-MM/NJ-EDMS1216580

Dimensional metrology One of the shapes was cut into two halves of 300 mm length (Half 1 and Half 2) and a dimensional metrology was carried out in two of their surfaces (Face A and Face R30.1) to check the straightness in the “as received” and “heat treated” states The curvature is slightly reduced after the heat treatment in all the samples but in “Half 2 Face A” EN Division-Materials and Metrology CERN/EN/MME-MM/NJ-EDMS1216580

Electrical conductivity /%IACS Temper state Electrical conductivity /%IACS AR 88.7±0.1 HT 90.7±0.1 The electrical conductivity is slightly increased after heat treatment Optical observations before etching AR HT There is not visible porosity in any of the temper states EN Division-Materials and Metrology CERN/EN/MME-MM/NJ-EDMS1216580

Optical observations after etching Longitudinal Transversal AR HT EN Division-Materials and Metrology CERN/EN/MME-MM/NJ-EDMS1216580

Optical observations For the longitudinal images (parallel to the extrusion direction) in the previous slide, we can state that the piece is ultra-fine grained and that shows a fibrous structure. In the transversal images (perpendicular to the extrusion direction), the grains are equiaxed The grain size is slightly increased after the heat treatment as visible in both longitudinal and transversal cross cuts In left image, relative to the HT specimen, we can observe some recrystallization near the center region of the cross-cut, parallel to the extrusion direction These large recrystallized grains are common in the annealing of the ODS coppers and are due to primary recrystallization. EN Division-Materials and Metrology CERN/EN/MME-MM/NJ-EDMS1216580

Hardness measurements Measurements parallel to the extrusion direction Measures in cross section 1 3 2 A B HRB (HV) Temper 1 2 3 AR 70.7±1.5 (137) 71.7±0.6 (139) 70.3±1.5 (137) HT 59.7±0.6 (118) 61.7±0.6 (121) 62±1 (122) Pure Cu (O) 45 HV5 Temper A B AR 137.2±2.8 147.2±3.3 HT 124.3±5 125.8±6.3 The hardness does not vary in the length direction and is depressed by the heat treatment as expected Before the heat treatment, the values of hardness in the thick part of the cross section (A) are lower than the thin part (B) close to the sharp edge, however, after the heat treatment they become similar (annealing phenomenon). CW 60% EN Division-Materials and Metrology CERN/EN/MME-MM/NJ-EDMS1216580

Tensile tests The heat treatment reduces the yield and tensile strength and increases ductility As expected, mechanical properties at cryogenic temperatures are improved including ductility EN Division-Materials and Metrology CERN/EN/MME-MM/NJ-EDMS1216580

A common behavior for pure copper is that the elongation decreases when the temperature increases finding a minimum of elongation at around 250° C % of flat fracture RT 4.2 K AR 66% 0% HT 33%

Comparison of results with supplier’s data and Glidcop (C15715) According to the values of oxide content, the most similar ODS copper is C15715 The closest tensile properties are observed are for a CW55% C15715 CW 99% 4K RT ECKA Granules ASM MME-MM measurement AR (includes + CW15% by Luvata) Reference (“fully cold worked” by Ecka) C15715 (CW 55%) Al oxide content (wt%) Not available 0.60 0.70 UTS (MPa) 414 360-400 427 Yield strength (MPa) 397 300-340 407 Elongation (%) 9.21 15-20 18 HRB 71 65-70 68 Electrical conductivity (%IACS) 88.7 88-91 92 EN Division-Materials and Metrology CERN/EN/MME-MM/NJ-EDMS1216580

Conclusions The dimensions of the shapes have to be improved. The cross section does not perfectly fit the planes and the straightness could be improved. This straightness in fact changes when the shape is heat treated and might lead to a problem of dimensional stability. The mechanical properties are comparable to the ones of CW 55% C15715 Strength and ductility increase at cold HT samples show a partial annealing No porosity was found The heat treatment have several effects in the properties: Changes the curvature of drawn shapes Increases the electrical conductivity Increases the grain size and promote some local recrystallization Homogenizes the hardness across the section EN Division-Materials and Metrology CERN/EN/MME-MM/NJ-EDMS1216580