Microstructural characteristics of a commercially pure Zr treated by pulsed laser at different powers
Microstructural characteristics of a commercially pure Zr treated by pulsed laser at different powers
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不同功率脉冲激光处理商业纯Zr的显微结构特征
DOI：
10.1016/j.matchar.2015.10.008
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发表时间：
2015-12
影响因子：
4.7
通讯作者：
W. Huang
中科院分区：
文献类型：
--
作者：
L. Chai;B. Chen;S. Wang;Z. Zhou;W. Huang
采用25和400 W脉冲激光处理工业纯Zr片材，利用电子背散射衍射（EBSD）和电子通道对比成像（ECC）技术对不同激光修饰区的微观结构特征进行了表征。结果表明：在400 W试样中，存在熔化区（MZ）、固相转变区（SSPTZ）和再结晶区（RXZ）三个具有明显显微组织特征的激光修饰区。MZ和SSPTZ主要由Widmanstätten组织组成，细小的析出相装饰着粗糙的α板边界。根据测量的α板的平均宽度，计算出两个区域的冷却速率为每秒几百度。对于RXZ，第二相颗粒（SPPs）在块状晶粒内呈线性分布，表明早期形成的板状结构发生了再结晶。利用EBSD对MZ板结构进行取向检测发现，根据Burgers取向关系，由同一β母晶转变而来的12种α变体均存在，这可能有助于抑制Zr合金中α变体的选择。对于25 W的样品，降低的激光功率不能熔化衬底，只有在非常高的冷却速率（> 6000°C/s）下发生固态相变。激光修饰区分别为β区和α+ β区，分别为SSPTZ-1和SSPTZ-2。这两个区域的板结构都是由无扩散马氏体相变产生的，这表明板内致密的纳米孪晶和没有spp。对于SSPTZ-2中未转化的α晶粒，虽然它们的初始块状形态保持不变，但它们的内部被许多亚晶粒所细分。此外，在25 W试样的马氏体板结构中，经常观察到3个α板聚集在一起，具有“压痕”形态，α板之间的边界取向偏差为60°/< 11 2′0>（第二次Burgers取向偏差）。
A commercially pure Zr sheet was treated by pulsed laser at two different powers (25 and 400 W) and microstructural features in various laser-modified zones were characterized by electron backscatter diffraction (EBSD) and electron channeling contrast imaging (ECC) techniques. Results show that in the 400 W specimen, there are three laser-modified zones with distinct microstructural characteristics: melting zone (MZ), solid state phase transformation zone (SSPTZ), and recrystallized zone (RXZ). Both the MZ and the SSPTZ are mainly composed of Widmanstätten structures with fine precipitates decorating coarse α plate boundaries. Based on measured mean widths of α plates, cooling rates experienced by both zones are calculated to be a few hundred degrees per second. For the RXZ, second phase particles (SPPs) are found to distribute linearly inside bulk grains, suggesting the occurrence of recrystallization from earlier formed plate structures. Orientation examination by EBSD on plate structures in the MZ reveals presence of all 12 α variants transformed from the same β parent grain according to the Burgers orientation relationship, which may shed some light on suppressing α-variant selection in Zr alloys. For the 25 W specimen, the decreased laser power cannot melt the substrate and only solid state phase transformation occurs at very high cooling rates (> 6000° C/s). The laser-modified zones could be distinguished as SSPTZ-1 or SSPTZ-2 for cooling from β or α+ β domains accordingly. Plate structures in both zones are produced by diffusionless martensitic transformation, as suggested by dense inner-plate nanotwins and absence of SPPs. For those untransformed α grains in the SSPTZ-2, although their initial bulk morphologies are maintained, slight subdivision by many subgrains in their interiors is noticed. In addition, aggregates of three α plates with the “indentation mark” morphology are often observed for the martensitic plate structures in the 25 W specimen and boundary misorientations between the α plates are found to be 60°/< 11 2 ̅ 0>(the second Burgers misorientation).
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DOI：
10.1007/s11431-009-0201-6
发表时间：
2009-08
期刊：
Science in China Series E: Technological Sciences
影响因子：
--
作者：
Yutao Zhu;Xi-Yan Zhang
通讯作者：
Yutao Zhu;Xi-Yan Zhang
影响因子：
9.4
作者：
M. Humbert;N. Gey
通讯作者：
M. Humbert;N. Gey
影响因子：
6.7
作者：
D. Peng;X. Bai;X. W. Chen;Q. G. Zhou;X. Liu;R. Yu
通讯作者：
D. Peng;X. Bai;X. W. Chen;Q. G. Zhou;X. Liu;R. Yu
影响因子：
3.1
作者：
R. Holt
通讯作者：
R. Holt
影响因子：
6.7
作者：
Costil, S.;Lamraoui, A.;Oltra, R.
通讯作者：
Oltra, R.