TWI657147B - A HIGH STRENGH Ni-BASE ALLOY - Google Patents
A HIGH STRENGH Ni-BASE ALLOY Download PDFInfo
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Abstract
本發明旨在提供一種高應力鎳基合金,其特徵在於其中之化學組成包含,以重量計:Ni為50.0~56.0wt%、Cr為18.0~20.0wt%、Nb為4.0~5.5wt%、Mo為2.8~3.3wt%、Al為1.3~1.6wt%、Ti為0.6~0.8wt%,其餘則由Fe及不可避免雜質所構成。 The present invention is directed to a high stress nickel-based alloy characterized in that the chemical composition comprises, by weight: Ni is 50.0 to 56.0 wt%, Cr is 18.0 to 20.0 wt%, and Nb is 4.0 to 5.5 wt%, Mo. It is 2.8 to 3.3 wt%, Al is 1.3 to 1.6 wt%, Ti is 0.6 to 0.8 wt%, and the rest is composed of Fe and unavoidable impurities.
Description
本發明係關於一種合金,特別是關於一種高應力鎳基超合金。 This invention relates to an alloy, and more particularly to a high stress nickel based superalloy.
鎳基合金是高溫合金中應用最廣,在高溫應用中屬於強度最高的一類合金,一般這類合金是應用在540℃以上的高溫環境,並依其使用場合,選用不同的合金設計,另可用於特殊耐蝕環境、高溫腐蝕環境、需具備高溫機械強度之設備,包含應用於航太、能源、石化工業或特殊電子/光電等領域,其中Ni-Cr合金一般稱之為Inconel合金,也就是常見的鎳基(耐熱)合金,主要可在氧化性介質條件下使用,而且若於Inconel中加入析出強化元素,則可形成析出硬化型鎳基合金,在高溫下仍保有良好的機械強度與抗蝕性,因此多用於噴射引擎的組件,如合金In718因具有優異的機械強度、好的加工性、可焊接性、以及適中的成本等特性,故為現今先進渦輪引擎耐高溫(650℃以下)零組件上最廣泛使用的材料之一。 Nickel-based alloys are the most widely used alloys in high-temperature alloys. They are the most high-strength alloys in high-temperature applications. Generally, these alloys are used in high-temperature environments above 540 °C, and depending on the application, different alloy designs are used. For special corrosion-resistant environments, high-temperature corrosive environments, and equipment requiring high-temperature mechanical strength, including in aerospace, energy, petrochemical industries or special electronics/photovoltaics, Ni-Cr alloys are generally called Inconel alloys, which are common. The nickel-based (heat-resistant) alloy can be mainly used under oxidizing medium conditions, and if a precipitation strengthening element is added to Inconel, a precipitation hardening type nickel-based alloy can be formed, and good mechanical strength and corrosion resistance are maintained at high temperatures. Therefore, the components used in the jet engine, such as Alloy In718, have excellent mechanical strength, good processability, weldability, and moderate cost. Therefore, the current advanced turbine engine is resistant to high temperatures (below 650 ° C). One of the most widely used materials on components.
提升鎳基合金強度可藉由改良合金成份來達成,例如增加特定合金元素含量(Ti,Al,Nb,Cr,C等)可改變合 金之顯微組織,進而改變合金之機械性質,當中市面上In718合金主要係靠γ’與γ”相在基地內的析出來強化,晶界則靠δ相與碳化物(MC)來達到強化的效果,另外Laves相係由Nb元素偏析所產生,屬較脆之有害相,於合金設計時需盡量避免Laves相之生成;同時商規In718合金因添加一定比例的Nb元素(4.75~5.50wt%),可形成γ”析出相進而強化In718機械性質,但此添加量亦會因Nb偏析而形成較脆之Laves有害相,且同時造成過多的δ相形成,造成機械性質下降。 Increasing the strength of the nickel-based alloy can be achieved by improving the alloy composition, for example, increasing the content of specific alloying elements (Ti, Al, Nb, Cr, C, etc.) can be changed. The microstructure of gold, in turn, changes the mechanical properties of the alloy. Among them, the In718 alloy on the market is mainly strengthened by the precipitation of γ' and γ" phases in the base, and the grain boundary is strengthened by the δ phase and carbide (MC). The effect is that the Laves phase is produced by the segregation of Nb element, which is a brittle harmful phase. The Laves phase should be avoided during the design of the alloy. At the same time, the In718 alloy is added with a certain proportion of Nb elements (4.75~5.50wt). %), can form γ" precipitated phase and strengthen the mechanical properties of In718, but this addition will also form a brittle Laves harmful phase due to Nb segregation, and at the same time cause excessive δ phase formation, resulting in a decrease in mechanical properties.
所以目前業界極需發展出一種具有優異的高應力鎳基合金,藉由合金成份優化設計可以改善合金機械性質,同時保有良好的可加工性、可焊接性等特性,如此一來,方能同時兼具機械特性與可加工性,以製備出高應力之鎳基合金。 Therefore, it is extremely necessary in the industry to develop an excellent high-stress nickel-based alloy, which can improve the mechanical properties of the alloy by optimizing the design of the alloy composition, while maintaining good processability, weldability and the like, so that simultaneously It combines mechanical properties and processability to produce a high-stress nickel-based alloy.
鑒於上述習知技術之缺點,本發明之主要目的在於提供一種高應力等軸晶鎳基合金,整合一真空熔煉、一真空鑄造及適當元素之添加等,以製備出高應力等軸晶鎳基合金。 In view of the above disadvantages of the prior art, the main object of the present invention is to provide a high stress equiaxed nickel base alloy, integrating a vacuum melting, a vacuum casting and the addition of appropriate elements to prepare a high stress equiaxed nickel base. alloy.
為了達到上述目的,根據本發明所提出之一方案,提供一種高應力鎳基合金,具有如下以重量百分比計之組成:Ni為50.0~56.0wt%、Cr為18.0~20.0wt%、Nb為4.0~5.5wt%、Mo為2.8~3.3wt%、Al為1.3~1.6wt%、Ti為0.6~0.8 wt%,其餘則由Fe及不可避免雜質所構成。 In order to achieve the above object, according to one aspect of the present invention, there is provided a high stress nickel-based alloy having the following composition in terms of weight percent: Ni is 50.0 to 56.0% by weight, Cr is 18.0 to 20.0% by weight, and Nb is 4.0. ~5.5wt%, Mo is 2.8~3.3wt%, Al is 1.3~1.6wt%, Ti is 0.6~0.8 Wt%, the rest consists of Fe and unavoidable impurities.
上述高應力鎳基合金係以真空感應爐進行熔煉,之後在真空的環境下進行真空精密鑄造,將熔融的合金液澆進陶模中,再進行冷卻即完成該鎳基合金之鑄錠工作。 The high-stress nickel-based alloy is smelted in a vacuum induction furnace, and then vacuum-precision casting is performed in a vacuum environment, and the molten alloy liquid is poured into the ceramic mold, and then cooling is performed to complete the ingot working of the nickel-based alloy.
上述鎳基合金之鑄錠,須進行進一步熱處理程序;該鎳基合金於本發明中進行三階段熱處理,其中,第一階段熱處理係以1000-1200℃對該鎳基合金之鑄錠進行熱處理一至二小時以上,然後以惰性氣體(例如氬氣)對該鎳基合金進行降溫、粹冷;第二階段熱處理係以900-1000℃對該鎳基合金之鑄錠進行熱處理至少一小時以上,然後以惰性氣體(例如氬氣)對該鎳基合金進行降溫、粹冷;第三階段則係以700-800℃對該鎳基合金之鑄錠進行熱處理八至九小時,接著進行爐冷至600-650℃並持溫八至九小時,然後以惰性氣體(例如氬氣)對該鎳基合金進行降溫、淬冷,製備出高應力鎳基合金。 The above-mentioned nickel-based alloy ingot is subjected to a further heat treatment process; the nickel-based alloy is subjected to a three-stage heat treatment in the present invention, wherein the first-stage heat treatment heat-treats the nickel-based alloy ingot at 1000-1200 ° C After more than two hours, the nickel-based alloy is cooled and cooled by an inert gas (for example, argon); the second-stage heat treatment heats the nickel-based alloy ingot at 900-1000 ° C for at least one hour, and then The nickel-based alloy is cooled and cooled by an inert gas such as argon; the third stage is heat-treated at 700-800 ° C for eight to nine hours, followed by furnace cooling to 600 The temperature is maintained at -650 ° C for eight to nine hours, and then the nickel-based alloy is cooled and quenched with an inert gas (for example, argon gas) to prepare a high-stress nickel-based alloy.
本發明之高應力鎳基合金,更可包含一W元素,其中,該W為<2.0wt%;本發明之高應力鎳基合金,更可包含一Ta元素,其中,該Ta為<2.0wt%。 The high-stress nickel-based alloy of the present invention may further comprise a W element, wherein the W is <2.0% by weight; the high-stress nickel-based alloy of the present invention may further comprise a Ta element, wherein the Ta is <2.0wt %.
以上之概述與接下來的詳細說明,皆是為了能進一步說明本創作達到預定目的所採取的方式、手段及功效。而有關本創作的其他目的及優點,將在後續的說明及圖式中加以闡述。 The above summary and the following detailed description are intended to further illustrate the manner, means and effects of the present invention to achieve the intended purpose. Other purposes and advantages of this creation will be explained in the following description and drawings.
以下係藉由特定的具體實例說明本創作之實施方式,熟悉此技藝之人士可由本說明書所揭示之內容輕易地了解本創作之優點及功效。 The embodiments of the present invention are described by way of specific examples, and those skilled in the art can readily understand the advantages and effects of the present invention from the disclosure of the present disclosure.
本案發明之合金設計以In718鎳基合金為基礎,藉由調整合金中的Al、Ti含量,增加鎳基合金中Ni3(Al,Ti)之γ’析出強化相的比例,同時減少過多的δ相析出以強化鎳基合金之機械強度,因為γ’相為L12有序FCC結構,屬高溫穩定相,不像一般金屬隨溫度上升機械強度降低,其機械強度與溫度成正比,具溫度愈高強度愈好之特性,雖然Al及Ti含量的增加可γ’相的數量,但是γ’相數量若過多,反而會造成合金脆性增加,容易於鑄造過程或使用過程中引發合金之脆裂現象,故本發明中鎳基合金之Al最佳含量應介於1.3~1.6wt%之間,Ti的含量應介於0.6~0.8wt%之間。 The alloy design of the invention is based on the In718 nickel-based alloy. By adjusting the Al and Ti contents in the alloy, the ratio of the γ' precipitation strengthening phase of Ni3 (Al, Ti) in the nickel-based alloy is increased, and the excessive δ phase is reduced. Precipitation to strengthen the mechanical strength of nickel-based alloys, because the γ' phase is an L12 ordered FCC structure, which is a high-temperature stable phase. Unlike ordinary metals, the mechanical strength decreases with temperature, and its mechanical strength is proportional to temperature, and the higher the temperature. The better the characteristics, although the increase of Al and Ti content can be the number of γ' phase, but if the number of γ' phase is too much, it will cause the alloy brittleness to increase, which is easy to cause the alloy to be brittle and cracked during the casting process or use. In the present invention, the optimum content of Al in the nickel-based alloy should be between 1.3 and 1.6 wt%, and the content of Ti should be between 0.6 and 0.8 wt%.
Nb元素在本發明合金中屬重要析出強化元素,適量的Nb元素可與Ni形成Ni3Nb之γ”與δ相,進而提升合金之機械強度,其中γ”相為BCT結構;δ相則為orthorhombic結構,兩者高溫穩定性皆較差,因此過量的析出反而造成機性下降,此外,添加過多的Nb,會使Nb易與其他合金元素產生偏析形成Laves相((Ni,Fe,Cr)2(Mo,Nb,Ti)),亦會導致機械強度下降,故本發明中鎳基合金之Nb最佳含量 應介於4.0~5.5wt%之間。 The Nb element is an important precipitation strengthening element in the alloy of the present invention, and an appropriate amount of Nb element can form a γ" and δ phase of Ni3Nb with Ni, thereby enhancing the mechanical strength of the alloy, wherein the γ" phase is a BCT structure; the δ phase is an orthorhombic structure. Both of them have poor high temperature stability, so excessive precipitation causes mechanical decline. In addition, excessive addition of Nb makes Nb easily segregate with other alloying elements to form Laves phase ((Ni, Fe, Cr) 2 (Mo , Nb, Ti)), which also causes a decrease in mechanical strength, so the optimum Nb content of the nickel-based alloy in the present invention It should be between 4.0 and 5.5 wt%.
Ta為析出強化元素,可取代部份Nb形成γ”相,補償為了避免形成Laves相而減少Nb之添加量,以提升合金強度,但Ta元素添加過多,易產生粗大之TaC型碳化物,該型碳化物容易成為破裂裂縫的起源,使合金強度降低,故本發明中鎳基合金之Ta元素含量控制在<2.0wt.%。 Ta is a precipitation strengthening element, which can replace part of Nb to form a γ" phase. The compensation is to reduce the amount of Nb added to avoid the formation of Laves phase, so as to increase the strength of the alloy, but the addition of Ta element is too large, and it is easy to produce coarse TaC type carbide. The type carbide is likely to be the origin of the fracture crack, and the strength of the alloy is lowered. Therefore, the Ta element content of the nickel-based alloy in the present invention is controlled to be <2.0 wt.%.
Mo在本發明中則是可提高γ’相穩定溫度,即提高γ’相的溶解溫度,但Mo含量過多也會有促使TCP(Topologically-close-packed)相及大尺寸塊狀碳化相形成的問題,TCP相是一種非常脆硬的相,容易因差排堆積造成應力集中讓其成為裂縫的起源,進而造成材料強度降低;另外,TCP相形成時會消耗掉γ基地中大量的固溶強化元素,造成γ基地的強度下降,故本發明中鎳基合金之Mo元素含量控制在2.8~3.3wt.%。 In the present invention, Mo can increase the γ' phase stable temperature, that is, increase the dissolution temperature of the γ' phase, but excessive Mo content also promotes the formation of a TCP (Topologically-closed-packed) phase and a large-sized bulk carbonized phase. The problem is that the TCP phase is a very brittle phase, which is easy to cause stress concentration due to the accumulation of differential discharge, which causes the material to be weakened. In addition, the formation of the TCP phase consumes a large amount of solid solution strengthening in the γ base. The element causes the strength of the γ base to decrease, so the Mo element content of the nickel-based alloy in the present invention is controlled to be 2.8 to 3.3 wt.%.
W在本發明中屬固溶強化元素,一般合金中的固溶強化主要是以提高原子間的結合力,產生晶格畸變(Lattice Distortion),降低固溶體中元素的擴散能力等,來達到強化合金基地的目的。經研究發現W含量並不能無限制提高,若含量過高會造成成份分佈不均勻,嚴重點會在合金內形成TCP有害相,導致合金強度下降。因此,為提高本發明鎳基合金之W元素含量控制在<2.0wt.%。 W is a solid solution strengthening element in the present invention. The solid solution strengthening in a general alloy is mainly to improve the bonding force between atoms, generate lattice distortion (Lattice Distortion), and reduce the diffusion ability of elements in a solid solution. Strengthen the purpose of the alloy base. It has been found that the W content can not be increased without limit. If the content is too high, the composition will be unevenly distributed, and a serious point will form a harmful phase of TCP in the alloy, resulting in a decrease in the strength of the alloy. Therefore, in order to improve the W element content of the nickel-based alloy of the present invention, it is controlled to be <2.0 wt.%.
根據前述之實驗結果,本發明開發一種高應力鎳 基合金,其化學組成為(以重量百分比計):Ni為50.0~56.0wt%、Cr為18.0~20.0wt%、Nb為4.0~5.5wt%、Mo為2.8~3.3wt%、Al為1.3~1.6wt%、Ti為0.6~0.8wt%,其餘則由Fe及不可避免雜質所構成;本案發明於不同的實施例,更可包含一Ta元素,其中,該Ta為<2.0wt%,或更可包含一W元素,其中,該W為<2.0wt%。 According to the foregoing experimental results, the present invention develops a high stress nickel The base alloy has a chemical composition (in terms of weight percent): Ni is 50.0 to 56.0 wt%, Cr is 18.0 to 20.0 wt%, Nb is 4.0 to 5.5 wt%, Mo is 2.8 to 3.3 wt%, and Al is 1.3. 1.6 wt%, Ti is 0.6-0.8 wt%, and the rest is composed of Fe and unavoidable impurities; the invention according to various embodiments may further comprise a Ta element, wherein the Ta is <2.0 wt%, or A W element may be included, wherein the W is <2.0 wt%.
實施例一 Embodiment 1
本發明之鎳基超合金,按其化學組成比例以真空感應爐進行熔煉,之後進行真空精密鑄造,將熔融的合金液澆進陶模中,為確保成份無誤並同時取樣,將合金試樣之成份以SPARK-AES進行成份分析,其結果(以重量百分比計)如表一所示:
實施例二 Embodiment 2
本發明之鎳基合金,按其化學組成比例以真空感應爐進行熔煉,之後進行真空精密鑄造,將熔融的合金液澆進陶模中,為確保成份無誤並同時取樣,將合金試樣之成份以SPARK-AES進行成份分析,其結果(以重量百分比計)如表三所示:
實施例三 Embodiment 3
本發明之鎳基合金,按其化學組成比例以真空感應爐進行熔煉,之後進行真空精密鑄造,將熔融的合金液澆進陶模中,為確保成份無誤並同時取樣,將合金試樣之成份以
SPARK-AES進行成份分析,其結果(以重量百分比計)如表五所示.
目前商用最常用的等軸晶鎳基超合金,主要有Mar-M247、In713LC及In718等合金為主,其中以In718合金的生產成本最低,故本發明選用In718合金作為比較參考,並參考In718合金之AMS 5383E航空材料規範當作室溫機械性質比較基準,相關室溫機械性質數據列於表七,經比較本發明合金與In718合金之室溫拉伸性能,顯示本發明之合金在最大拉伸強度UTS及降伏強度YS皆明顯優於商規In718,且延伸率亦明顯大於商規規範,顯示藉由本發明之成份優化 設計,可同時增加優化型In718之室溫機械強度以及延性。 At present, the most commonly used equiaxed nickel-base superalloys are mainly alloys such as Mar-M247, In713LC and In718. Among them, the production cost of In718 alloy is the lowest, so the invention uses In718 alloy as a comparative reference, and refers to In718 alloy. The AMS 5383E aeronautical material specification is used as a benchmark for room temperature mechanical properties. The relevant room temperature mechanical properties data are listed in Table 7. The room temperature tensile properties of the alloy of the present invention and the In718 alloy are compared to show that the alloy of the present invention is stretched at maximum. Both the strength UTS and the drop strength YS are significantly better than the commercial specification In718, and the elongation is also significantly larger than the commercial specification, showing that the composition is optimized by the present invention. Designed to increase the room temperature mechanical strength and ductility of the optimized In718.
上述之實施例僅為例示性說明本創作之特點及功效,非用以限制本創作之實質技術內容的範圍。任何熟悉此技藝之人士均可在不違背創作之精神及範疇下,對上述實施例進行修飾與變化。因此,本創作之權利保護範圍,應如後述之申請專利範圍所列。 The above-described embodiments are merely illustrative of the features and functions of the present invention and are not intended to limit the scope of the technical content of the present invention. Any person skilled in the art can modify and change the above embodiments without departing from the spirit and scope of the creation. Therefore, the scope of protection of this creation should be as listed in the scope of the patent application described later.
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CN113319468A (en) * | 2021-06-16 | 2021-08-31 | 哈尔滨焊接研究院有限公司 | Component design method of nuclear power nickel-based alloy welding wire capable of preventing welding cracks and nuclear power nickel-based alloy welding wire |
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