PSI - Issue 2_B

Su Jie et al. / Procedia Structural Integrity 2 (2016) 2222–2229

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Su Jie et al./ Structural Integrity Procedia 00 (2016) 000 – 000

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Fig. 3. Microscopic morphology of the microstructure in central area of specimen

a

b

CSP

LP

Fig. 4. Particle distribution in specimen: (a) Large particle; (b) Cluster of small particles.

The damage evolution process during in situ tensile test can be divided into three stages, single cracking of LPs and CSPs, multiple cracking of LPs and CSPs and coalescence of micro cracks. Micro cracks (MCs) firstly appear due to self-cracking of LPs, as shown in Fig. 5. MCs also initiate in CSPs by either breaking small particles or debonding interfaces of small particles (Fig. 6). The MCs are usually in mode I and approximately perpendicular to tensile direction. They are brittle, extending rapidly until being arrested at the interfaces of LPs and CSPs with Al matrix.

LP

tensile direction

Fig. 5. Micro crack initiating at 1 st damage stage

a

b

CSP

CSP

tensile direction

tensile direction