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Please use this identifier to cite or link to this item: http://ntour.ntou.edu.tw:8080/ir/handle/987654321/9483

Title: IN718超合金雷射表面改質技術研究
Laser Surface Modification of IN 718 Superalloy
Authors: 蔡履文
Contributors: NTOU:Institute of Materials Engineering
Keywords: IN718超合金;雷射加工;表面改質
IN 718 superalloy;Laser machining;Surface modification
Date: 2001-08
Issue Date: 2011-06-28T07:09:18Z
Publisher: 行政院國家科學委員會
Abstract: 本研究為探討Inconel 718 (IN718)板材在大氣、氣態氫、及硫化氫水溶液充氫不同時段後,疲勞裂縫成長特性之比較,此外雷射熱處理對板材疲勞裂縫成長之影響亦被探討。時效試件經雷射處理由於強化析出物重新固溶入基地中,導致試件表面硬度下降,增加雷射處理速率時,其退火深度相對減少。殘留應力量測結果顯示:經雷射熱處理之中心位置顯示殘留張應力,而在裂縫尖端前1mm處為殘留壓應力區。疲勞裂縫成長試驗結果顯示雖然IN718合金在固溶及時效狀態,存在明顯強度及延性的差異,但兩者之疲勞裂縫成長特性卻大體相同。經雷射熱處理之CT試片,熱處理區前方區域因殘留壓應力之影響,使疲勞裂縫成長速率減慢甚至無法生長,而在氣態氫環境或經硫化氫水溶液充氫後,因氫原子在IN718材料內部擴散速率極慢或IN718氫脆性低,故氫脆導致疲勞裂縫成長加速現象並未產生。
The object of this work is to study the fatigue crack growth behavior of heat-treated In718 alloy tested in various conditions, including laboratory air, gaseous hydrogen and pre-charging in saturated H/sub 2/S solution for different periods of time. Although the difference in tensile properties between solution-annealed and aged specimens is quite large, experimental results indicate that both specimens have nearly the similar fatigue properties in air and gaseous hydrogen. For laser-treated specimens, the initial high resistance to crack growth is noticed, as compared with that of the aged base material. The retardation of crack growth ahead of laser track has been attributed to the presence of residual compressive stresses ahead of crack tip.
Relation: NSC90-2216-E019-008
URI: http://ntour.ntou.edu.tw/ir/handle/987654321/9483
Appears in Collections:[材料工程研究所] 研究計畫

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