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Please use this identifier to cite or link to this item: http://ntour.ntou.edu.tw:8080/ir/handle/987654321/13639

Title: Ti-15V-3Cr-3Al-3Sn母材和銲件機械性質之研究
Mechanical Properties of Ti-15V-3Cr-3Al-3Sn Solution-Annealed and Welds
Authors: Yen-Chieh Wu
吳彥傑
Contributors: NTOU:Institute of Materials Engineering
國立臺灣海洋大學:材料工程研究所
Keywords: Ti-15V-3Cr-3Al-3Sn;缺口拉伸;破裂韌性;機械性質
Ti-15V-3Cr-3Al-3Sn;Notch tensile strength;Fracture toughness;Mechanical properties
Date: 2010
Issue Date: 2011-06-30T07:24:29Z
Abstract: 本研究中使用5KW二氧化碳雷射對Ti-15V-3Cr-3Al-3Sn合金板材進行銲接,之後將母材與銲件經由317~600℃時效處理,比較母材與銲件其機械性質之差異性。 對Ti-15V-3Cr-3Al-3Sn板材進行平板拉伸實驗,結果顯示,於 371℃時效後會引發脆性破壞,而在更高的時效溫度(538℃),破裂模式將由脆性破裂轉變為延性破裂。又由缺口拉伸和衝擊試驗中,低於317℃銲件具有較高的缺口拉伸強度及衝擊值,當時效溫度達371℃時,缺口強度和衝擊值均有驟降之結果,且破斷面較為脆性;隨時效溫度上升,α相析出促使材料性質有所轉變,缺口強度和衝擊值均會有所增加,代表材料適用於低於317℃和較高時效溫度下。 對Ti-15V-3Cr-3Al-3Sn板材進行疲勞裂縫成長試驗,溫度低於317℃前疲勞裂縫成長速率較不受影響,於371℃時效時,裂縫成長速率有明顯加快之情形,且破裂面之呈現較為平坦,隨時效溫度上升,裂縫成長速率有逐漸下降的現象,代表時效溫度升高有助於改善材料之特性。
In this study, the influence of post-weld heat treatments (PWHTs) on the mechanical properties and microstructures of Ti-15V-3Cr-3Sn-3Al (Ti-15-3) laser welds, which were aged in the temperature range of 317 to 593 oC, were determined. Moreover, the mechanical properties of the welds were compared with the un-welded base plate in the same aging condition. The ultimate tensile strength of the aged plate varied in the same manner as the hardness, but inversely with ductility. The specimens aged at 371 oC (under-aged specimen) were the most susceptible to notch brittleness among the specimens being tested, regardless of aged plate or weld. An obvious rise in notched tensile strength (NTS) was obtained for the specimens aged at 538 oC or higher. The fracture toughness of the plate was consistent with its NTS, i.e., higher fracture toughness corresponding to greater NTS. The as-welded weld possessed the highest impact toughness in all specimens. However, aging treatment at 371 oC caused an abrupt drop in weld’s ability to resist unstable crack growth. Besides, the welds aged at/above 371 oC had lower impact toughness than the un-weld plate aged at the same temperature. The results of fatigue crack growth tests showed the un-welded specimen aged at 371 oC had a slightly higher fatigue crack growth rate than the other aged specimens
URI: http://ethesys.lib.ntou.edu.tw/cdrfb3/record/#G0M97550005
http://ntour.ntou.edu.tw/ir/handle/987654321/13639
Appears in Collections:[材料工程研究所] 博碩士論文

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