激光熔覆沉积Ti-20V-15Cr合金的组织演化与硬度

发布时间：2018-05-17 16:30

本文选题：激光熔覆沉积 + Ti-V-Cr　；参考：《应用激光》2017年01期

【摘要】：以混合的Ti、V、Cr元素粉末为原料,采用CO_2激光器激光熔覆沉积Ti-20V-15Cr阻燃钛合金,并针对合金沉积层的显微组织、冶金质量以及显微硬度展开研究。结果表明,采用CO_2激光器制备的Ti-20V-15Cr阻燃钛合金,沉积试样成分分布均匀、组织致密、未出现裂纹、熔合不良等缺陷;沉积试样整体由单相!晶粒组成,但原始!晶粒形态对激光熔覆沉积工艺下的熔池凝固条件变化极为敏感;沉积试样底部、中部和顶部区域沿沉积层生长方向依次出现三种形态的晶粒生长:柱状晶、类等轴晶和等轴晶。基于合金凝固柱状晶/等轴晶转变模型以及激光熔覆沉积过程试样底部、中部和顶部熔池凝固条件分析,揭示了激光熔覆沉积Ti-20V-15Cr合金的凝固组织形成机理,采用显微硬度计对沉积试样各区域显微硬度进行测试。测试结果表明,沉积试样各区域硬度分布均匀,未出现明显波动,平均显微硬度约为372HV。
[Abstract]:Ti-20V-15Cr flame-retardant titanium alloy was deposited by laser cladding with CO_2 laser using mixed Ti-V Cr powder as raw material. The microstructure, metallurgical quality and microhardness of the deposited layer were studied. The results show that the composition of Ti-20V-15Cr flame retardant titanium alloy prepared by CO_2 laser is uniform, the microstructure is dense, there are no cracks, the fusion is poor, and the deposited sample is composed of single phase. Grain composition, but primitive! The grain morphology is very sensitive to the change of solidification conditions of the molten pool under laser cladding deposition, and three kinds of grain growth along the growth direction of the deposition layer appear at the bottom, the middle and the top of the deposited sample: columnar crystal, equiaxed crystal and equiaxed crystal. Based on the solidification columnar / equiaxed crystal transformation model and the analysis of solidification conditions in the bottom, middle and top molten pool of the sample during laser cladding deposition, the mechanism of solidification microstructure of Ti-20V-15Cr alloy deposited by laser cladding is revealed. The microhardness of the deposited samples was measured by microhardness meter. The results show that the hardness distribution of the deposited samples is uniform and there is no obvious fluctuation. The average microhardness is about 372HV.
【作者单位】：长安大学材料科学与工程学院;西北工业大学凝固技术国家重点实验室;
【基金】：国家自然科学基金资助项目(项目编号:51401033) 国家重点研发计划资助项目(项目编号:2016YFB1100103,2016YFB0700301) 中国博士后科学基金资助项目(项目编号:2016M592731) 陕西省自然科学基础研究计划资助项目(项目编号:2016JQ5022)
【分类号】：TG665

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