Deformation Mechanism of AZ31B Magnesium Alloy Under Different Loading Paths

doi:10.1007/s40195-015-0342-5

Abstract

Abstract:

Deformation and texture evolution of AZ31B magnesium (Mg) alloy sheet under uniaxial tension, compression, and reverse loading after different pre-strain (compression and tension) were investigated experimentally. The results indicate that the pre-compressive strain remarkably affects the reverse tensile yield stress and the width of the detwinning-dominant stage during inverse tension process. Similar to stressCstrain curve of the uniaxial compression, the curve of reverse tensile yield value also has S shape, and its minimum value is only 38 MPa. The relationship between pre-compressive strain and the width of detwinning-dominant stage presents a linear growth, and the greater the pre-compressive strain is, the smaller the strain hardening rate of the detwinning-slip-dominant stage is. Compared with the reverse tension under pre-compression, the influence of the pre-tension deformation on the deformation mechanism of subsequent compression is relatively simple. With the increase in pre-tension strain, the yield stress of the reverse loading is rising.

Key words: AZ31B magnesium alloy, Loading path, Detwinning, Texture, Yield stress

Shuai-Feng Chen, Li Zheng, Shi-Hong Zhang, Hong-Wu Song, Ming Cheng. Deformation Mechanism of AZ31B Magnesium Alloy Under Different Loading Paths[J]. Acta Metallurgica Sinica (English Letters), 2015, 28(12): 1426-1434.

Figures/Tables 14

Fig.1 Dimensions of specimen (unit mm)

Table 1 Program of unidirectional loading tests

Specimen	Strain path	Strain (%)	Texture test
No. 1	Monotonic tension	Till failure	√
No. 2	Monotonic compression	Till failure	×
No. 3	Monotonic compression	3	√
No. 4	Monotonic compression	7	√
No. 5	Monotonic compression	11	√

Table 2 Program of compression-tension and tension-compression loading tests

Specimen	Strain path	Pre-compression strain (%)	Strain of reverse loading (%)	Texture test
No. 6	Tension-compression	4	7	×
No. 7	Tension-compression	5	9	×
No. 8	Tension compression	8	12	×
No. 9	Compression-tension	3	10	×
No. 10	Compression-tension	4	10	×
No. 11	Compression-tension	5	10	×
No. 12	Compression-tension	6	10	×
No. 13	Compression-tension	7	10	×
No. 14	Compression-tension	8	10	×
No. 15	Compression-tension	8	3	√
No. 16	Compression-tension	8	5	√
No. 17	Compression-tension	8	8	√

Fig.2 Pole figure of as-received extruded magnesium sheet

Fig.3 Strain hardening rate curve of tension, compression and dominate deformation mechanism distribution along compression stress-strain curve

Fig.4 Pole figures of extruded magnesium sheet under 3% a, 7% b, 11% c compression strains along ED

Fig.5 Stress-strain curve of extruded magnesium sheet during compression-tension along ED and strain hardening rate curve during reverse tension

Fig.6 Pole figures under different reverse tension strains of 3% a, 7% b, 11% c and with 8% compression strain along ED

Fig.7 Stress-strain curves of extruded magnesium sheet under compression-tension loading along ED with different pre-compression strains

Fig.8 Relations between yield stress of reverse tension and pre-compression strain

Fig.9 Strain hardening rate curves of reverse tension with different pre-compressive strain along ED

Fig.10 Relation between pre-compressive strain and detwinning-dominant deformation strain in reverse tension

Fig.11 Stress-strain curves of extruded magnesium sheet under tension-compression loading along ED with different pretension strain

Fig.12 Relation between yield strength of reverse compression and pretension strain

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