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通过对挤压坯预成形AEZ611镁合金进行锻压成形及时效热处理,研究了塑性形变及时效过程中显微组织及力学性能的变化规律。结果表明,在箱式电阻炉中时效处理,晶界较粗且晶粒大小不均,油浴中时效晶界变细,有利于合金力学性能的改善。同时AEZ611镁合金力学性能及显微组织对温度较为敏感。时效温度升高至200℃时,第二相的析出速度加快,且析出相分布变得均匀,细小的黑色点状相弥散分布于晶界上;随着时效保温时间的延长,稀土相Al4Ce相在镁合金的弥散数量增加,且晶粒大小均匀,使合金的力学性能得以进一步改善,稀土的弥散数量、大小及形貌对AEZ611镁合金的力学性能有着重要的影响。最佳时效工艺为油浴中时效390℃×1h+200℃×20h,其抗拉强度可达311MPa,屈服强度达到232MPa,伸长率为11%。
AEZ611 magnesium alloy preform extrusion forging and aging heat treatment, plastic deformation and aging process microstructure and mechanical properties of the law of change. The results show that aging treatment in the box type resistance furnace has coarse grain boundaries and uneven grain size, and the aging grain boundaries become thinner in the oil bath, which is in favor of improving the mechanical properties of the alloy. At the same time AEZ611 magnesium alloy mechanical properties and microstructure is more sensitive to temperature. When the aging temperature is increased to 200 ℃, the precipitation rate of the second phase increases and the precipitated phase becomes uniform. The fine black phase disperses in the grain boundary. With the prolonging of holding time, the phase of Al4Ce phase The dispersion of magnesium alloy increases, and the grain size is uniform, so the mechanical properties of the alloy can be further improved. The amount, size and morphology of rare earth dispersion have an important influence on the mechanical properties of AEZ611 magnesium alloy. The best aging process for oil bath aging 390 ℃ × 1h +200 ℃ × 20h, the tensile strength of up to 311MPa, yield strength of 232MPa, elongation of 11%.