TY - JOUR
T1 - Assessment of low-cycle fatigue life of Sn-3.5mass%Ag-X (X = Bi or Cu) alloy by strain range partitioning approach
AU - Kariya, Yoshiharu
AU - Morihata, Tomoo
AU - Hazawa, Eisaku
AU - Otsuka, Masahisa
PY - 2001/9
Y1 - 2001/9
N2 - The fatigue lives and damage mechanisms of Sn-Ag-X (X = Bi and Cu) solder alloys under creep-fatigue interaction mode have been investigated, and the adaptability of the strain partitioning approach to the creep-fatigue of these alloys was examined. Symmetrical and asymmetrical saw-tooth strain profiles components (i.e., fast-fast, fast-slow, slow-fast and slow-slow) were employed. Application of the slow-slow strain mode did not have an effect on fatigue lives of the alloys under investigation. Transgranular fracture observed on the fracture surfaces suggests that creep damage might be cancelled under slow-slow mode. The fatigue lives of all alloys were dramatically reduced under slow-fast mode, which is attributed to intergranular cavitation and fracture during tensile creep flow. On the other hand, the compression creep component generated by fast-slow mode also significantly reduced the life of Sn-3.5Ag and Sn-3.5Ag-1Cu, while the component did not affect the life of Sn-3.5Ag-xBi (x =2 and 5). The four partitioned strain ranges (i.e., Δεpp, Δεpc, Δεcp, and Δεcc) versus life relationships were established in all alloys tested. Thus, it is confirmed that the creep-fatigue life of these alloys can be quantitatively predicted by the strain partitioning approach for any type of inelastic strain cycling.
AB - The fatigue lives and damage mechanisms of Sn-Ag-X (X = Bi and Cu) solder alloys under creep-fatigue interaction mode have been investigated, and the adaptability of the strain partitioning approach to the creep-fatigue of these alloys was examined. Symmetrical and asymmetrical saw-tooth strain profiles components (i.e., fast-fast, fast-slow, slow-fast and slow-slow) were employed. Application of the slow-slow strain mode did not have an effect on fatigue lives of the alloys under investigation. Transgranular fracture observed on the fracture surfaces suggests that creep damage might be cancelled under slow-slow mode. The fatigue lives of all alloys were dramatically reduced under slow-fast mode, which is attributed to intergranular cavitation and fracture during tensile creep flow. On the other hand, the compression creep component generated by fast-slow mode also significantly reduced the life of Sn-3.5Ag and Sn-3.5Ag-1Cu, while the component did not affect the life of Sn-3.5Ag-xBi (x =2 and 5). The four partitioned strain ranges (i.e., Δεpp, Δεpc, Δεcp, and Δεcc) versus life relationships were established in all alloys tested. Thus, it is confirmed that the creep-fatigue life of these alloys can be quantitatively predicted by the strain partitioning approach for any type of inelastic strain cycling.
KW - Coffin-Manson plots
KW - Creep-fatigue interactions
KW - Strain range partitioning
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U2 - 10.1007/s11664-001-0148-2
DO - 10.1007/s11664-001-0148-2
M3 - Article
AN - SCOPUS:0035455438
VL - 30
SP - 1184
EP - 1189
JO - Journal of Electronic Materials
JF - Journal of Electronic Materials
SN - 0361-5235
IS - 9
ER -