Studies of the Influence of Beam Profile and Cooling Conditions on the Laser Deposition of a Directionally-Solidified Superalloy.
Studies of the Influence of Beam Profile and Cooling Conditions on the Laser Deposition of a Directionally-Solidified Superalloy.
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光束轮廓和冷却条件对定向凝固高温合金激光沉积影响的研究
DOI：
10.3390/ma11020240
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发表时间：
2018-02-04
期刊：
影响因子：
--
通讯作者：
Chang B
中科院分区：
文献类型：
--
作者：
Yang S;Du D;Chang B
在单晶和定向凝固高温合金的激光沉积中，需要通过有效抑制柱状到等轴转变来形成具有高柱状晶体积分数的激光沉积。本文在定向凝固高温合金IC10激光沉积中，实验研究了光束轮廓（圆形和方形）和冷却条件（自然冷却和强制冷却）对沉积物几何形貌和微观结构的影响，并通过激光沉积热过程的数值模拟揭示了影响机制。结果表明，无论采用自然冷却还是强制冷却条件，方形激光束比圆形激光束获得的沉积物更宽、更薄。由于对两种激光束轮廓应用强制冷却降低了基板温度，沉积物的高度和接触角显着增加。自然冷却条件下，方形激光束在沉积物中心和边缘均形成柱状晶，而圆形激光束仅在沉积物中心形成柱状晶；在强制冷却条件下，无论激光束轮廓如何，沉积物的中心和边缘都会形成柱状晶粒。沉积物高度方向热梯度和凝固速度的高比例有利于形成柱状晶体积分数较高的沉积物。
In the laser deposition of single crystal and directionally-solidified superalloys, it is desired to form laser deposits with high volume fractions of columnar grains by suppressing the columnar-to-equiaxed transition efficiently. In this paper, the influence of beam profile (circular and square shapes) and cooling conditions (natural cooling and forced cooling) on the geometric morphology and microstructure of deposits were experimentally studied in the laser deposition of a directionally-solidified superalloy, IC10, and the mechanisms of influence were revealed through a numerical simulation of the thermal processes during laser deposition. The results show that wider and thinner deposits were obtained with the square laser beam than those with the circular laser beam, regardless of whether natural or forced cooling conditions was used. The heights and contact angles of deposits were notably increased due to the reduced substrate temperatures by the application of forced cooling for both laser beam profiles. Under natural cooling conditions, columnar grains formed epitaxially at both the center and the edges of the deposits with the square laser beam, but only at the center of the deposits with the circular laser beam; under forced cooling conditions, columnar grains formed at both the center and the edges of deposits regardless of the laser beam profile. The high ratios of thermal gradient and solidification velocity in the height direction of the deposits were favorable to forming deposits with higher volume fractions of columnar grains.
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影响因子：
5.4
作者：
Shang, S.;Wellburn, Dan;Liu, C. S.
通讯作者：
Liu, C. S.
激光立体成形熔池扩展的力学和能量分析
影响因子：
6.7
作者：
Yu, Jun;Lin, Xin;Huang, Weidong
通讯作者：
Huang, Weidong
DOI：
10.1016/0025-5416(84)90201-5
发表时间：
1984-01-01
期刊：
MATERIALS SCIENCE AND ENGINEERING
影响因子：
--
作者：
HUNT, JD
通讯作者：
HUNT, JD
影响因子：
6.2
作者：
Chen, Yuan;Lu, Fenggui;Li, Zhuguo
通讯作者：
Li, Zhuguo
影响因子：
9.4
作者：
Gäumann, M;Bezençon, C;Kurz, W
通讯作者：
Kurz, W