ZHU Zuming Institute of Metal Reasearch
,
Academia Sinica
,
Shenyang
,
PRC.
材料科学技术（英文）
The longitudinal(L),long-transverse(T) and short-transverse(S)orientated samples of precipitation-strengthened 7075-T651 aluminum alloy were examined. The acoustic emission(AE)characteristics measured during tensile deformation in the alloy were related to prior aging treatment and orienta- tions of samples. A rms AE peak occurred in all the samples at plastic strain greater than one percent. The heights of peaks have been measured as a function of prior heat treatment.The shift of the peak location was dependent on heat treat- ment in samples with L- and T-orientation. The pre-yield,burst-type emission(PYBE)were observed in S-orientated samples.The behaviours of PYBE were as a function of prior ageing treat- ment too. The stress and plastic strains at which the AE peak stress were generated were consistent with the peaks arising from the fracture and debonding of inclusions.Waveform frequency analysis of AE signals and fractographic observa- tions using SEM as well as data of microhardness and charpy test were also consistent with be- haviours of AE,that is,high stress required for the rms peak or the initiation of the PYBE, was higher for the heat treatment,at which the interface between inclusion and matrix was weaker.
关键词:
acoustic emission
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