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分别以预合金粉末和混合元素粉末为原料进行激光多层沉积Ti-6A-4V合金,采用XRD研究了预合金粉末、混合元素粉末和沉积试样的相组成,采用金相显微镜研究了沉积试样的凝固组织.结果表明,预合金法激光多层沉积Ti-6Al-4V合金的凝固组织由外延生长的柱状晶组成,且随激光功率的提高,合金凝固组织倾向于由柱状晶转变为等轴晶;随着激光功率由1600 W增加至2700 W,混合元素法激光多层沉积Ti-6Al-4V合金的凝固组织则由粗大等轴晶逐渐转变为外延生长的柱状晶.扫描速率对合金凝固组织的影响较小.对混合焓对合金凝固组织的影响进行了讨论.
The laser multi-layer deposition of Ti-6A-4V alloy with pre-alloyed powder and mixed-elemental powder as raw materials respectively. The phase composition of pre-alloyed powder, mixed-elemental powder and deposited sample was investigated by XRD. The results show that the solidified microstructure of the Ti-6Al-4V alloy deposited by the pre-alloyed laser is composed of epitaxial growth of columnar crystals, and with the increase of laser power, the solidified structure of the alloy tends to change from columnar crystals to Axis.The crystal structure of Ti-6Al-4V alloy deposited by mixed-element method gradually changed from coarse equiaxed to epitaxial-grown columnar as the laser power increased from 1600 W to 2700 W. Scanning rate of the alloy The effect of mixed enthalpy on the solidified structure of the alloy is discussed.