Aging characteristics of thermomechanically processed Cu-9Ni-6Sn alloy

Kim, Sang Shik; Rhu, Jae Chul; Jung, Yun Chul; Han, Seung Zeon; Kim, Chang Joo

doi:10.1016/s1359-6462(98)00400-x

Cited by 29 publications

(9 citation statements)

References 5 publications

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“…The bending fatigue strength of Cu-6Ni-2Mn-2Sn-2Al alloys is much superior to that of PM Cu-7.5Ni-5Sn alloys. [4] Conclusively, it is demonstrated that the hot workability of newly developed Cu-6Ni-2Mn-2Sn-2Al alloy can be substantially improved with a small amount of Zr addition. The Sn segregation along the grain boundaries, which causes intergranular cracking, was greatly reduced with a Zr addition.…”

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confidence: 91%

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Effect of Zr addition on hot workability of Cu-6Ni-2Mn-2Sn-2Al alloy

Han

Kong

Kim

et al. 2002

Metall Mater Trans A

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Cu-9Ni-6Sn alloy has been developed as a possible substitute for high-strength, precipitation-hardened Cu-Be Fig. 1-Macroscopic views of (a) 90 pct hot-swaged Cu-6Ni-2Mn-2Sn-2Al alloy and (b) 10 pct hot-swaged Cu-9Ni-6Sn alloy. alloys in the various applications of electronic industry. [1][2][3][4][5][6][7] However, it is often impracticable to produce sheet products from Cu-9Ni-6Sn alloy due to the severe cracking during hot working. It has been previously reported that Sn-rich segregates formed during solidification are responsible for hot cracking. [8] There have been considerable research activities to solve the hot cracking problem, including the powder metallurgy (PM) technique and the lowering of Sn content. [9] Powder metallurgy processed high Sn-containing Cu-Ni-Sn alloys can be readily rolled down to 0.2-mm-thick sheet, but they have an inherent problem of high production cost. The previous study conducted by the authors has suggested that Cu-6Ni-2Mn-2Sn-2Al alloy is hot workable with a reduced production cost and reasonable physical properties compared to Cu-9Ni-6Sn alloys. The Sn content of 2 pct in the Cu-6Ni-2Mn-2Sn-2Al alloy makes it possible to be hot rolled to produce the sheet products. The Mn is isomorphous to Cu and can partially replace expensive Ni that is beneficial to castability and tensile strength. The addition of Al, which is a strong solid solution strengthener in Cu, compensates the reduced tensile strength as a result of lower Sn content. In conducting research, it was found that the addition of a small amount of Zr further improved the hot workability of Cu-6Ni-2Mn-2Sn-2Al alloy significantly. The objective of the present study therefore was to examine the effects of beneficial Zr addition on the hot workability of Cu-6Ni-2Mn-2Sn-2Al alloy.Cu-6Ni-2Mn-2Sn-2Al alloys without and with Zr addition of 0.3 wt pct were prepared using permanent mold casting in the form of either 25 mm round bar or 25-mm-thick plate, respectively. A round bar with a 25-mm diameter was hot swaged at 850 ЊC to 8-mm diameter rod and air cooled. A plate with a 25-mm-thick plate was also hot rolled to 1-mm-thick sheet at 850 ЊC. Some specimens were aged at either 400 ЊC or 450 ЊC, respectively, for 1 to 7 hours. Tensile tests and Vickers hardness tests were conducted for selected specimens. Either a flat or cylindrical specimen, respectively, with a gage length of 25.4 mm was prepared from the rolled sheet or the swaged bar products, respectively. Bending fatigue tests were performed according to ASTM B593, using a Krouse-type bending fatigue machine, at an R ratio of Ϫ1 and test frequency of 20 Hz. Scanning electron microscope (SEM) and optical SEUNGZEON HAN, Senior Researcher, MANSIK KONG, Researcher, and CHANGJOO KIM, Principal Researcher, are with Materials Engineering Department, Korea Institute of Machinery and Materials, Changwon, Korea. SANGSHIK KIM, Associate Professor, is with the Division Fig. 2-SEM micrographs of cracked areas in 90 pct hot-swaged Cu-6Ni-of Materials Science and Engineering, Engine...

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confidence: 91%

“…alloys in the various applications of electronic industry. [1][2][3][4][5][6][7] However, it is often impracticable to produce sheet products from Cu-9Ni-6Sn alloy due to the severe cracking during hot working. It has been previously reported that Sn-rich segregates formed during solidification are responsible for hot cracking.…”

mentioning

confidence: 99%

Effect of Zr addition on hot workability of Cu-6Ni-2Mn-2Sn-2Al alloy

Han

Kong

Kim

et al. 2002

Metall Mater Trans A

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“…Some authors believed that the age-hardening of Cu-Ni-Sn alloys came from the spinodal decomposition [ 6 , 7 ]. However, the papers also demonstrated that the age-hardening derived from the formation of coherent DO 22 phase [ 8 , 9 , 10 ]. So, many researches focused on the investigations of aging characterization of Cu-Ni-Sn alloys.…”

Section: Introductionmentioning

confidence: 99%

Effect of Ni Content on Microstructure and Characterization of Cu-Ni-Sn Alloys

Wang

et al. 2018

Materials

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Cu-xNi-5Sn (wt %) alloys with a different Ni content were prepared by a powder metallurgy method. The effect of Ni content on the hardness and yield strength of Cu-xNi-5Sn (wt %) alloys was investigated. The microstructure, composition, and morphology of Cu-xNi-5Sn (wt %) alloys were observed by X-ray diffraction (XRD), scanning electron microscopy (SEM) with energy dispersive spectroscopy (EDS), and cold field emission scanning electron microscope (FESEM), respectively. Results indicate that the hardness and yield strength firstly increase and then decrease with the increase of Ni content and reach up to a maximum when Ni content is 12.5 wt %. Furthermore, the formation of the sandwich structure and needle-like phase is found in the grain, the grain boundary and intragranular precipitates are rich in both the Ni and Sn phase. The formation of the inerratic and suitable lamellar precipitates of sandwich structure and needle-like phase can be responsible for the good mechanical properties of the Cu-12.5Ni-5Sn alloy after aging treatment. The sandwich structure and need-like phase that were observed by FESEM can contribute to clarify the morphology of Cu-Ni-Sn alloys.

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“…Cu-Ni-Sn alloys are considered as an attractive substitute for Cu-Be alloys, and have been widely applied to the manufacture of switches, connectors, and spring components in the electronic industries [ 1 , 2 , 3 ]. Among Cu-Ni-Sn systems, Cu-15Ni-8Sn (known as C72900) has the highest strength.…”

Section: Introductionmentioning

confidence: 99%

Improving the Mechanical Properties of Cu-15Ni-8Sn Alloys by Addition of Titanium

et al. 2017

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Abstract:The effect of Ti addition on the microstructure and mechanical properties of Cu-15Ni-8Sn alloys was investigated. Optical microscopy (OM), scanning electronic microscopy (SEM), and transmission electron microscopy (TEM) were used to determine grain size and distribution of the second phases in the alloys. The results indicate that the tensile properties of Cu-15Ni-8Sn alloys are improved significantly with Ti addition. Tensile elongation increased from 2.7% for the alloy without Ti to 17.9% for the alloy with 0.3% Ti, while tensile strength was maintained and even increased from 935 MPa to 1024 MPa. The improvement of the mechanical properties of Cu-15Ni-8Sn alloys by the addition of Ti is attributed to the grain refinement and suppression of discontinuous precipitation during heat treatment.

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Aging characteristics of thermomechanically processed Cu-9Ni-6Sn alloy

Cited by 29 publications

References 5 publications

Effect of Zr addition on hot workability of Cu-6Ni-2Mn-2Sn-2Al alloy

Effect of Zr addition on hot workability of Cu-6Ni-2Mn-2Sn-2Al alloy

Effect of Ni Content on Microstructure and Characterization of Cu-Ni-Sn Alloys

Improving the Mechanical Properties of Cu-15Ni-8Sn Alloys by Addition of Titanium

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