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研究生:歐仲仁
研究生(外文):Chun-Jen Ou
論文名稱:微量合金法添加硼與碳對鎳-19矽-3鈮基介金屬合金微結構及機械行為之研究
論文名稱(外文):Study on the Microstructure Evolution and Mechanical Behaviors of the Ni-19Si-3Nb Based Intermetallic Alloys Doped with Boron and Carbon by using Microalloying Methods
指導教授:鄭憲清
指導教授(外文):Shian-Ching Jang
學位類別:碩士
校院名稱:義守大學
系所名稱:材料科學與工程學系
學門:工程學門
學類:材料工程學類
論文種類:學術論文
論文出版年:2000
畢業學年度:88
語文別:中文
論文頁數:113
中文關鍵詞:鎳矽化合物介金屬微量合金法微結構機械行為
外文關鍵詞:Nickel silicidesintermetallicmicroalloymicrostructuremechanical property
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鎳矽介金屬合金 (Ni3Si,有序之面心立方 L12結構)為一種有別於其他金屬之特殊結構,尤其在高溫環境時,其優良的抗侵蝕、抗氧化,及降伏強度隨溫度之上升而升高的特性 (最大之降伏強度發生於 700℃),使此合金在高溫應用上優於其他金屬;然而,鎳矽二元合金相似於鎳鋁合金,在室溫環境下有著脆性破壞的現象;以至於如何增加晶界之契合性使合金提升延性,達到多用途的應用成為尚待解決的問題之一。
經由前人實驗研究之結果,以鎳-19矽-3鈮(Ni-19Si-3Nb)基介金屬合金,應用微量合金法(次元素添加量約小於600 ppm)以化學計量之方式同時添加微量硼與碳元素,在氬氣氣氛保護之下,使用電弧熔煉、墜落式鑄造法製造成鑄塊胚料,續以真空退火爐進行鑄塊 1080℃、四小時均質化與700℃、十小時時效化處理,而後取樣進行成份分析驗證;並藉由其組織、破斷面之光學顯微鏡、掃瞄式電子顯微鏡及穿透式電子顯微鏡觀察,與拉伸試驗、微硬度之機械行為等變化,以獲得改善該合金材料脆性之最佳微量合金硼與碳元素之添加值。
本實驗之研究結果證實,當添加微量硼與碳元素各為300 ppm及200ppm時,顯示該合金有最佳之機械性質組合;其極限拉伸應力 (UTS)由原 727 MPa 增加至1224 MPa,延率從 4.3﹪提升至12﹪。由於添加微量元素、均質化與時效熱處理後,對合金之相變化、相含量與相結構並無太大影響,但造成析出物之形態鈍化、呈現粒狀析出散佈之較具延性與強度之微結構,並證實該合金在添加硼與碳元素後,對其機械行為確有明顯之改善效果。

Intermetallic compounds based on Ni3Si (ordered fcc L12 structure) offer a number of interesting properties for structural applications in aggressive environments at elevated temperature. These interesting properties include the excellent corrosion and oxidation resistance at both ambient and elevated temperatures, good specific strength in comparison with other materials, increasing yield strength as a function of temperature, and a peak yield strength occurring at about 700℃. However, similar to the Ni3Al, binary Ni3Si suffers from grain boundary embrittlement at room temperature. Therefore, how to improve its grain boundary adhesion will be the critical point of increasing the ductility and widespread the applications of Ni-Si intermetallic alloys.
According to the pre-studies, we select the Ni-19Si-3Nb alloy as the based alloy to investigate the effect of adding boron and carbon by means of arc melting and drop casting under argon atmospheres, and then homogenizing and aging in a vacuum annealing furnace of 5×10-5 torr at 1080℃ for 4 hours and 700℃ for 10 hours respectively.
The evolution of microstructure change and mechanical properties of the Ni-19Si-3Nb-xB-yC alloys were characterized by x-ray diffraction, DTA, SEM, TEM, EPMA, microhardness test, Vickers hardness test, and tensile tests. The results of x-ray diffraction, DTA and TEM could not resolve any change of phase content for the Ni-19-Si-3Nb alloy with different boron and carbon content.
But, the consequences of the fracture behavior of the Ni-19Si-3Nb alloys with different carbon and boron additions exhibits significant change from brittle mode to ductile mode. The optimum additions of carbon and boron for improving the mechanical properties of the based alloy will occur at the combination of 200-ppm carbon and 300-ppm boron addition. Their elongation will increase from originally 4.3﹪to nearly 12﹪, the ultimate tensile stress (UTS)from 727 MPa to 1224 MPa, and the yield stress also from 705 MPa to 840 MPa. Meanwhile, the morphology of precipitates transformed a lot of blunt-edged equiaxed precipitates existing in the grain boundary and in the matrix.
According to the fracture surface observed, they reveal that an obviously fracture mode change from intergranular to transgranular due to the grain boundary strengthening by increasing the boron and carbon additions in this alloys. Meanwhile, these results can supply an information for researching into the grain boundary strengthening mechanism in the future.

英文摘要………………………………………………………………………………I
中文摘要………………………………………………………………………………III
目錄……………………………………………………………………………………V
表目錄…………………………………………………………………………………VII
程式目錄………………………………………………………………………………VII
圖目錄…………………………………………………………………………………VII
第一章前言…………………………………………………………………………..01
第二章研究背景………………………………………………………………….…02
第三章理論基礎……………………………………………………………….……04
3-1 影響鎳矽基合金延性之因素………………………………………………04
3-2 鎳矽基合金之延韌性改善…………………………………………………08
3-3 鎳矽基合金與鎳矽鈮基合金………………………………………………10
3-4 硼之微偏析對鎳矽基合金之影響…………………………………………16
3-5 碳元素微偏析於鎳矽基合金之影響………………………………………17
3-6 微量添加硼或碳元素對鎳基合金之微結構與機械行為的影響…………18
第四章實驗流程……………………………………………………….……………21
4-1 合金試片之先前準備………………………………………………………21
4-1-1 合金之組成…………………………………………………………21
4-1-2 電弧熔解與墜落式鑄造……………………………………………21
4-1-3 熱處理 (均質化與時效) …………………………………………30
4-1-4 試片取樣……………………………………………………………30
4-2 微觀組織分析…………………………….……………………………….30
4-2-1 輝光放電分析儀 (GDS) 與碳硫分析…………………………….35
4-2-2 X光繞射 (XRD)…………..…………………………………………35
4-2-3 熱差分析儀……………………….…………………………………35
4-2-4 光學顯微鏡 (OM) ………………………………………….………36
4-2-5 掃瞄式電子顯微鏡 (SEM) 與 EDS…………………………………36
4-2-6電子微探儀 (EPMA) …………………………………………………36
4-2-7 穿透式電子顯微鏡 (TEM) 與擇域繞射 (SAD) ………………..…36
4-2-8 拉伸測試 (MTS) 與維式硬度 (Vickers hardness)
、微小硬度 (Microhardness) 測試………….37
第五章 結果與討論………………………………………………………………….…38
5-1 輝光放電分析(G.D.S.)與碳硫分析量測…………………………………38
5-2 X光繞射分析(XRD)…………………………………………………...…38
5-3 熱差分析 (DTA)……………………………………………………..……42
5-4 拉伸測試與硬度測試……………..…………………………………………42
5-4-1 拉伸測試 (Tensile Test)……………………………..….…44
5-4-2 硬度測試 (Hardness Test)…………………………..………47
5-5 光學顯微鏡觀察(OM)…………………………………………..…………51
5-6 掃瞄式電子顯微鏡觀察(SEM)與EDS…………………………..…………51
5-7 電子微探儀分析 (EPMA)………………………………………...………88
5-8 穿透式電子顯微鏡(TEM)與擇域繞射(SAD)…………………..………99
第六章 總結………………………………………………………………….……….105
參考文獻………………………………………………………………………….……107
表 目 錄
表 4-1 鎳矽鈮合金內各組成元素之比例……………………………………………26
表 4-2 鎳-19矽-3鈮基合金以微量合金法添加硼與碳合金內各元素之特性……27
表 5-1 鎳-19矽-3鈮基介金屬合金添加不同硼與碳之
輝光放電分析(GDS)與碳硫分析……………………………….………..39
程 式 目 錄
程式 4-1 Q-basic 程式之原子比重與重量比重轉換……………………….…..…..28
圖 目 錄
圖 3-1 (a) Ni3Si 之 L12 有序 f.c.c. 結構
(b) 硼或碳格隙型原子於 Ni3Si 之位置………………………………..……5
圖 3-2 鎳矽二元相圖與主要之結晶結構………………………………………..…11
圖 3-3 鎳-鈮二元相圖………………………………………………………….……12
圖 3-4 鈮-矽二元相圖…………………………………………………………….…12
圖 3-5 鎳-19矽基合金添加不同比例鈮元素後對 X光繞射之影響…………..…14
圖 3-6 鎳-19矽基合金添加不同比例鈮元素後對晶格常數之改變…………..…14
圖 3-7 鎳-19矽基合金之 TEM 影像與擇域繞射圖………………………….……15
圖 4-1 實驗流程…………………………………………….………………….……22
圖 4-1-1 試片製作示意圖……………………………………………………….……23
圖 4-2 (a) 氬焊機外觀圖 、 (b) 電弧熔解爐 (Arc-melt furnace)………..…24
圖 4-3 電弧熔解爐結構圖……………………………………………………….……25
圖 4-4 墜落式鑄造爐結構圖……………………………………………………….…31
圖 4-5 石英管之管狀真空退火爐結構圖………………………………………….…32
圖 4-6 快速凝固鑄件剖斷面…………………………………………………………33
圖 4-7拉伸試片之標準示意圖………………………………………………….……34
圖 5-1 鎳-19矽-3鈮基介金屬合金添加不同硼與碳之 XRD 分析…………..…….41
圖 5-2 不同硼與碳含量之鎳-19矽-3鈮基介金屬合金熱差分析比較
(升溫速率為 10℃/min)……………………………………………….……43
圖 5-3 不同硼與碳含量對鎳-19矽-3鈮基介金屬合金之
極限抗拉強度(U.T.S.)關係…………………………………………….…45
圖 5-4 不同硼與碳含量對鎳-19矽-3鈮基介金屬合金之
降伏強度(Y.S.)關係…………………………………………….…………46
圖 5-5 不同硼與碳含量對鎳-19矽-3鈮基介金屬合金之
伸長量(Elongation)關係……………………………………………..……48
圖 5-6 不同硼含量對鎳-19矽-3鈮-0.05碳介金屬合金之
微小硬度關係圖………………………………………………………………49
圖 5-7 不同硼含量對鎳-19矽-3鈮-0.1碳介金屬合金之微小硬度關係圖…….…50
圖 5-8 不同硼與碳含量對鎳-19矽-3鈮基介金屬合金之維氏硬度關係………….52
圖 5-9 鎳-19矽-3鈮基介金屬合金拉伸試片側向破斷面之光學顯微鏡觀察………53
圖 5-10 鎳-19矽-3鈮基介金屬經鑄造後(a)、均質化(b)及時效後(c)
之掃瞄式電子顯微鏡觀察……………………………………………………58
圖 5-11 鎳-19矽-3鈮-0.1硼-0.05碳介金屬經鑄造後(a)、均質化(b)
及時效後(c)之掃瞄式電子顯微鏡觀察……………………………………59
圖 5-12 鎳-19矽-3鈮-0.1硼-0.1碳介金屬經鑄造後(a)、均質化(b)
及時效後(c)之掃瞄式電子顯微鏡觀察……………………………………60
圖 5-13 鎳-19矽-3鈮-0.15硼-0.05碳介金屬經鑄造後(a)、均質化(b)
及時效後(c)之掃瞄式電子顯微鏡觀察……………………………………61
圖 5-14 鎳-19矽-3鈮-0.15硼-0.1碳介金屬經鑄造後(a)、均質化(b)
及時效後(c)之掃瞄式電子顯微鏡觀察……………………………………62
圖 5-15 鎳-19矽-3鈮-0.2硼-0.05碳介金屬經鑄造後(a)、均質化(b)
及時效後(c)之掃瞄式電子顯微鏡觀察……………………………………63
圖 5-16 鎳-19矽-3鈮-0.2硼-0.1碳介金屬經鑄造後(a)、均質化(b)
及時效後(c)之掃瞄式電子顯微鏡觀察……………………………………64
圖 5-17-1 鎳-19矽-3鈮基介金屬合金電子顯微鏡觀察(500倍)…………………66
圖 5-17-2 鎳-19矽-3鈮基介金屬合金電子顯微鏡觀察(1000倍)…………………70
圖 5-18-1 鎳-19矽-3鈮基介金屬合金之電子顯微鏡觀察與 EDS 成份分析…...….74
圖 5-18-2 鎳-19矽-3鈮-0.1硼-0.05碳基介金屬合金之電子顯微鏡觀察與
EDS 成份分析………………………………………………………….…76
圖 5-18-3 鎳-19矽-3鈮-0.1 硼-0.1碳基介金屬合金之電子顯微鏡觀察與
EDS 成份分析……………………………………………………………78
圖 5-18-4 鎳-19矽-3鈮-0.15硼-0.05碳基介金屬合金之電子顯微鏡觀察與
EDS 成份分析……………………………………………………….……80
圖 5-18-5 鎳-19矽-3鈮-0.15硼-0.1碳基介金屬合金之電子顯微鏡觀察與
EDS 成份分析……………………………………………………….……82
圖 5-18-6 鎳-19矽-3鈮-0.2硼-0.05碳基介金屬合金之電子顯微鏡觀察與
EDS 成份分析……………………………………………………….……84
圖 5-18-7 鎳-19矽-3鈮-0.2硼-0.1碳基介金屬合金之電子顯微鏡觀察與
EDS 成份分析……………………………………………………….……86
圖 5-19-1 鎳-19矽-3鈮基介金屬合金拉伸後破斷面電子顯微鏡觀察 (200倍)…...92
圖 5-19-2 鎳-19矽-3鈮基介金屬合金拉伸後破斷面電子顯微鏡觀察 (1500倍)….96
圖 5-20-1 鎳-19矽-3鈮-0.2硼-0.1碳之EPMA觀察…………………………………97
圖5-20-2 鎳-19矽-3鈮-0.2硼-0.1碳之EPMA 觀察…………………………………98
圖 5-21 鎳-19矽-3鈮-0.2硼-0.1碳之富鈮析出物明視野影像
(a)及擇域繞射圖(b)………………………………………………………100
圖 5-22 鎳-19矽-3鈮-0.2硼-0.1碳之富鈮析出物暗視野影像
(a)及擇域繞射圖(b)……………………………………………………101
圖 5-23 鎳-19矽-3鈮-0.2硼-0.1碳之基地明視野影像
(a)及擇域繞射圖(b)……………………………………………………102
圖 5-24 鎳-19矽-3鈮-0.2硼-0.1碳之基地明視野影像
(a)及擇域繞射圖(b)……………………………………………………103
圖 5-25 鎳-19矽-3鈮-0.2硼-0.1碳之基地暗視野影像
(a)及擇域繞射圖(b)……………………………………………………104

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