Precipitation hardening of Cu–Ti–Cr alloys

Markandeya, R.; Nagarjuna, S.; Sarma, D. S.

doi:10.1016/j.msea.2003.12.002

Cited by 62 publications

(25 citation statements)

References 17 publications

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“…Se puede observar que en esta aleación ternaria no aparece la curva correspondiente a la formación del Cu 3 Ti, lo cual podría indicar que el cobalto inhibe la precipitación de dicha fase [ cuencia de la diminución del contenido de titanio en la aleación por la formación de las fases intermetálicas. La etapa 6 podría corresponder a la formación de fases intermetálicas de Cr 2 Ti [20][21][22] , mientras que las etapas 7 y 9 corresponderían a precipitados de Cu 4 Ti y Cu 3 Ti, respectivamente.…”

Section: Resultados Y Discusionunclassified

“…Por otra parte, la literatura indica que la máxima resistencia mecá-nica de las aleaciones Cu-Ti está asociada con la nucleación y crecimiento de las partículas de Cu 4 Ti y que ésta resistencia, decrece como resultado de la precipitación discontinua de partículas estables de Cu 3 Ti [4,6,10 y 11] . Investigaciones anteriores [12][13][14][15][16][17][18][19][20][21][22] , han estudiado el efecto de ciertos aleantes, tales como V, Al, Sn, B, Co, Cd y Cr, en el endurecimiento de las aleaciones de Cu-Ti. De acuerdo a la literatura, el vanadio es un elemento que retardaría la precipitación de la fase Cu 4 Ti y aceleraría la formación de Cu 3 Ti [12] .…”

Section: Introduccionunclassified

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Influencia de la adición de cobalto y cromo en el proceso de precipitación en una aleación de Cu-4Ti

Donoso¹

2010

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Influencia de la adición de cobalto y cromo en el proceso de precipitación en una aleación de Cu-4Ti (•) E. Donoso* ResumenMediante calorimetría diferencial de barrido (DSC) y medidas de microdureza se estudió la influencia de la adición de 0,5 atómico % de cobalto y 1 atómico % de cromo en el endurecimiento por precipitación en una aleación de Cu-4Ti. El análisis de las curvas calorimétricas muestra, en la aleación binaria, la presencia de dos reacciones exotérmicas traslapadas (etapas 1 y 2), atribuidas a la formación de partículas de Cu 4 Ti y Cu 3 Ti en la matriz de cobre. Las curvas DSC para la aleación de Cu-4Ti-0,5Co muestra tres efectos exotérmicos (etapas 3 y 4 traslapadas y etapa 5), asociadas a la formación de las fases Ti 2 Co, TiCo y Cu 4 Ti, respectivamente. Las curvas DSC para la aleación de Cu-4Ti-1Cr muestra tres reacciones exotérmicas (etapas 6, 7 y 9) y un pico endotérmico (etapa 8). Las reacciones exotérmicas corresponden a la formación de partículas de Cr 2 Ti, Cu 4 Ti y Cu 3 Ti, respectivamente, y la reacción endotérmica está asociada a la disolución de las partículas de Cr 2 Ti. Las energías de activación, evaluadas a partir del método de Kissinger modificado, resultaron más bajas que las correspondientes a la difusión de cobalto, cromo y titanio en cobre. Los parámetros cinéticos se obtuvieron a partir de un método de convolución basado en el formalismo de Johnson-Mehl-Avrami (JMA). Medidas de microdureza Vickers corroboraron la formación de las fases indicadas. Estas medidas también confirmaron el efecto de la adición de cobalto y cromo en el endurecimiento de la aleación binaria. Palabras claveCobre; Cu-Ti; Precipitación; Microcalorimetría. Influence of cobalt and chromium additions on the precipitation processes in a Cu-4Ti alloys AbstractThe influence of 0.5 % atomic cobalt and 1 % atomic chromium additions on the precipitation hardening of Cu-4Ti alloy was studied by differential scanning calorimetry (DSC) and microhardeness measurements. The analysis of the calorimetric curves, for binary alloy, shows the presence of two overlapping exothermic reactions (stages 1 and 2) attributed to the formation of Cu 4 Ti and Cu 3 Ti particles in the copper matrix, respectively. DSC curves for Cu-4Ti-0,5Co alloy shows three exothermic effects (overlapping stages 3 and 4 and stage 5) associated to the formation of phases Ti 2 Co, TiCo and Cu 4 Ti, respectively. DSC curves for Cu-4Ti-1Cr alloy shows three exothermic reactions (stages 6, 7 and 9) and one endothermic peak (stage 8). The exothermic reactions correspond to the formation of phases Cr 2 Ti, Cu 4 Ti and Cu 3 Ti, respectively, and the endothermic reaction are attributed to the Cr 2 Ti dissolution. The activation energies calculated using the modified Kissinger method were lower than the ones corresponding to diffusion of cobalt, chromium and titanium in copper. Kinetic parameters were obtained by a convolution method based on the Johnson-Mehl-Avrami (JMA) formalism. Microhardness measurements confirmed the formation of the mentioned pha...

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Section: Resultados Y Discusionunclassified

Section: Introduccionunclassified

Influencia de la adición de cobalto y cromo en el proceso de precipitación en una aleación de Cu-4Ti

Donoso¹

2010

REVMETAL

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“…After prolonged aging, the cellular precipitation of the stable orthorhombic β Cu 4 Ti phase takes place by nucleation and growth on grain boundaries which is the main cause for the decrease in the mechanical strength in the later stage of aging 1 . The mechanical strength of Cu-Ti alloys has been improved either by the addition of a third alloying element such as Chromium, zirconium, carbon, nitrogen or hydrogen [9][10][11] or by using cold work previously to the aging treatment 12,13 . In the former case, the precipitation sequence was similar to that observed in the binary alloy; however, the presence of a different precipitates such as titanium chromide, nitride, carbide or hydride was also reported to occur during aging [9][10][11] .…”

Section: Introductionmentioning

confidence: 99%

“…In the former case, the precipitation sequence was similar to that observed in the binary alloy; however, the presence of a different precipitates such as titanium chromide, nitride, carbide or hydride was also reported to occur during aging [9][10][11] . In the latter case, the cold work, used after solution treatment and quenching, has been reported 12,14 to promote the precipitation of titanium on dislocations and to inhibit the precipitation of the β´ Cu 4 Ti and β Cu 4 Ti phases during aging.…”

Section: Introductionmentioning

confidence: 99%

Analysis of β´(Cu4Ti) Precipitation During Isothermal Aging of a Cu-4wt.%Ti Alloy

et al. 2018

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This work analyzed experimental and numerically the growth kinetics of β´precipitation of a Cu4wt.%Ti alloy after aging at 400, 500 and 600 °C for times from 0.0166 h to 200 h. Results indicated that the precipitation process is almost controlled by nucleation and growth during aging at 400 °C, originating a slow growth kinetics of precipitation. In contrast, the coarsening of precipitates dominates the precipitation process during aging at 500 and 600 °C. The interfacial energy of interface between the a matrix phase and β´ precipitates was determined to be about 0.1135, 0.0980 and 0.0725 Jm -2 for aging at 400, 500 and 600 °C, respectively. These values suggest a coherent interface which is in agreement with the flat faces of β´ cuboid precipitates. Calculated Time-Temperature-Precipitation diagram for the β´ precipitation indicated good agreement with experimental results. Precipitation hardening was higher for the slower growth kinetics of precipitation.

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“…The application of sever plastic deformation process 8) or the addition of a third element 9) has been proposed as alternative approaches to improve the balance between the mechanical properties and conductivity of Cu-Ti alloys. In recent years, Semboshi et al found that when Cu-Ti alloys are aged in a hydrogen (H) atmosphere, their conductivity increases rapidly and significantly, 10) showing that the balance between strength and conductivity can be considerably improved by optimizing the aging conditions.…”

Section: Introductionmentioning

confidence: 99%

Precipitation Behavior and Properties of Cu-Ti Alloys with Added Nitrogen

et al. 2015

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The effects of adding nitrogen (N) to age-hardenable Cu-Ti alloys on their microstructure, hardness, and conductivity have been investigated. It was found that the aging of Cu-Ti-(0.060.6) mol% N alloys resulted in the continuous formation of finely precipitated needleshaped ¡-Cu 4 Ti grains and the discontinuous formation of coarse cellular components composed of a stable ¢-Cu 4 Ti and Cu solid solution at the grain boundaries, in a manner similar to that in the case of conventional Cu-Ti alloys without any N. Furthermore, a small amount of granular TiN particles was also formed in Cu-Ti-N alloys. The hardening behavior of Cu-Ti-N alloys was similar to that of Cu-Ti alloys without N. This similarity was attributed to the finely dispersed precipitation of ¡-Cu 4 Ti that was similar between Cu-Ti alloys with and without N. The electrical conductivity of Cu-Ti-N alloys increased more steeply than that of Cu-Ti alloys without N. This is because in the case of Cu-Ti-N alloys, the coprecipitation of ¡-Cu 4 Ti, ¢-Cu 4 Ti, and TiN efficiently reduced the Ti concentration in the matrix. Thus, the conductivity of peak-hardened Cu-Ti-N alloys can be improved by optimizing the N concentration and aging temperature.

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Precipitation hardening of Cu–Ti–Cr alloys

Cited by 62 publications

References 17 publications

Influencia de la adición de cobalto y cromo en el proceso de precipitación en una aleación de Cu-4Ti

Influencia de la adición de cobalto y cromo en el proceso de precipitación en una aleación de Cu-4Ti

Analysis of β´(Cu4Ti) Precipitation During Isothermal Aging of a Cu-4wt.%Ti Alloy

Precipitation Behavior and Properties of Cu-Ti Alloys with Added Nitrogen

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