【摘要】 镁合金 AZ91D 中加入质量分数为1%的 La 时,合金在常温下的抗拉强度和延伸率分别增大了21%和101．2%,并且腐蚀速率下降为原 AZ91D 的47．2%．其中力学性能的提高主要是由于加入 La 后形成了（Al,Mg）₁₁La₃强化相,同时,细化了β相．耐蚀性的提高则是由于 La 的加入形成了具有类网状结构的β相,这种类网状结构的β相能有效地抑制腐蚀过程的进行,从而提高了镁合金的耐蚀性．当 La 加入量进一步增大时,合金力学性能缓慢增大,但其耐蚀性却明显降低,特别是当 La 达到2%时,合金的腐蚀速率甚至高于原合金的腐蚀速率．这主要是由于过多的 La 导致镁合金基体α相的 Al 含量大大降低, 从而降低了镁合金的耐蚀性．更多还原

【Abstract】 The microstructure,mechanical property and corrosion behavior of AZ91D with addition of lanthanum were investigated.When adding 1% lanthanum,the ultimate tensile strength and the elongation increased by 21.1% and 101.2%,respectively,which resulted from the refinement of the β phase and the formation of（Al,Mg）₁₁La₃ strengthening phase,while the corrosion rate decreased to 47.2%.But when La content was over 1%,the corrosion rate increased.Small amount of La addition could form the small β phase grains similar to net-like structure,which could restrain the corrosion at some extent.Large amount of La addition caused the depletion of A1 in α matrix,which increased the corrosion rate.更多还原