本研究探討不同電位、應變速率及熱處理對鎳基182合金銲道，於0.05 M鹽酸水溶液中應力腐蝕破裂行為(stress corrosion cracking, SCC)的影響。利用慢應變速率拉伸試驗(slow strain rate test, SSRT)來評估應力腐蝕破裂的敏感性，拉伸試驗的應變速率範圍為8.3×10-6 s-1 ~ 8.3×10-8 s-1。
由金相組織觀察結果發現，鎳基182合金銲道經1300℃/1h固溶處理，可改變顯微結構成為等軸晶粒的微觀組織，其尺寸大小約為100 ~ 200 μm，有效達到均質化的效果。此外經X-ray繞射分析、維式硬度量測結果顯示，熱處理會提高堆銲後 ，特別是(111)面的繞射強度、優選方位、結晶結構並增加硬度大小。而在空氣中進行拉伸試驗，發現經均質化之試片，其極限抗拉強度(ultimate tensile stress, UTS)增強約10 %，總延伸率(total percentage of elongation, TEL)更是提升50 %之多，有較佳的抗形變能力。然而，經均質化條件者，可能因熱處理過程，造成化學成分及結晶結構重組排列，於0.05 M HCl水溶液中顯現較高的金屬溶解速率，耐蝕性質呈現較差。
經SSRT試驗結果顯示，未經熱處理及經1300℃/1h固溶處理之鎳基182合金銲道，控制在8.3×10-7 s-1的應變速率下，於鹽酸溶液中，在開路電位、活性轉鈍性及過鈍態的電位範圍，鎳基182合金銲道會發生應力腐蝕破裂行為(SCC)；而在陰極電位下，拉伸行為表現為所有電位下者最低，顯示該材料於氫的影響下，有非常高的破裂敏感性，得知環境誘發破裂行為(environmentally-assisted cracking, EAC)與外加電位有非常密切的關係。
而在-50 mVSCE的電位條件下，未經熱處理之鎳基182合金銲道，隨著應變拉伸速率的下降，抗應力腐蝕破裂行為更弱，呈現出氫誘發破裂(hydrogen assisted cracking, HAC)的機制，顯示氫於此破壞過程中扮演一個重要的角色。

The effects of applied potential, strain rate and heat treatment on stress corrosion cracking (SCC) of Alloy 182 in 0.05 M hydrochloric acid solution were investigated. Slow strain rate tests (SSRT) were employed to evaluate the SCC resistance.
Alloy 182 weld, with heat treatment, was also examined by three-dimensional metallgraph observation, X-ray diffraction, Vicker’s microhardness and SSRTs. All experimental results presented that Alloy 182 weld homogenized with 1300℃/1h heat treatment would make a transformation on microstructure, crystal structure, microhardness and tensile behavior. But the electrochemical behavior of homogenized Alloy 182 weld in 0.05 M HCl solution showed less corrosion resistance by potentiodynamic polarization curve measurements.
Furthermore the SSRT results demonstrated that the cracking behavior of Alloy 182 weld with/without heat treatment was strongly dependent on the electrochemical potential. The results showed that Alloy 182 weld was most susceptible to cracking in 0.05 M hydrochloric acid solution under cathodic polarization condition. In the active-to-passive transition as well as in the transpassive potential regions, the weld also suffered environmentally-assisted cracking (EAC). However, in the passive potential region, the weld was immune to EAC.
The SSRT results also exhibited the strain rate-dependent EAC behavior of Alloy 182 weld in 0.05 M HCl solution. At an applied potential of -50 mVSCE (in the active-to-passive transition region), the ductility decreased with decreasing strain rate, indicating the decrease in EAC resistance. The significant loss of ductility at a strain rate as low as 8.3×10-7 s-1 indicated that hydrogen-assisted cracking (HAC) participate in the cracking process under anodic polarization condition.

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