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研究了纯镁在350℃往复挤压2,4,8道次,以及在250℃,350℃,450℃往复挤压2道次的组织和力学性能的变化规律。结果表明,纯镁经350℃往复挤压后,组织显著细化,挤压道次从2增加到8时,晶粒尺寸无明显变化,而屈服强度下降,延伸率提高。通过电子背散射衍射技术(EBSD)发现纯镁在350℃往复挤压2,4,8道次后,形成{}0001基面与挤压方向分别约成25°,30°,40°夹角的织构,且织构强度增加,基面滑移系的Schmid因子上升。纯镁在250℃,350℃,450℃往复挤压2道次后,随着挤压温度下降,晶粒尺寸减小,屈服强度上升,屈服强度和晶粒尺寸之间的关系可表述为σs=5.4+338.6d-12。
The changes of microstructure and mechanical properties of pure magnesium after reciprocating extrusion at 350 ℃ for 2, 4, and 8 passes and reciprocating extrusion at 250 ℃, 350 ℃ and 450 ℃ for 2 times were studied. The results show that the microstructure of the pure magnesium is remarkably refined after it is reciprocated and extruded at 350 ℃. When the extrusion pass increases from 2 to 8, the grain size does not change obviously, but the yield strength decreases and the elongation increases. It was found by electron backscatter diffraction (EBSD) that after the pure magnesium was reciprocated for 2, 4, and 8 passes at 350 ℃, the angle between the {0001} base and the extrusion direction was about 25 °, 30 ° and 40 ° respectively And the texture strength increases, Schmid factor of base slip system increases. When pure magnesium is reciprocated and extruded twice at 250 ℃, 350 ℃ and 450 ℃, the relationship between the yield strength and the grain size can be expressed as σs as the extrusion temperature decreases, the grain size decreases and the yield strength increases. = 5.4 + 338.6d-12.