1307367 玖、發明說明： 【發明所屬之技術領域】 本發明係關於一種藉由鑄造、施以方向性凝固 (directional solidification)而製造含有鎳、锰和鎵 之形狀記憶金屬合金的方法，其使得形狀記憶金屬合金之 晶體結構獲得較大的結晶以及具有預期的方向性。 【先前技術】 磁激或磁控金屬係一種可使由其製得之物件在受控制 下重新成形的材料--其由於外部、可調整之磁場的作用 而捲繞、伸展和彎折。記憶金屬的性狀在例如芬蘭專利第 1 0 1，5 6 3號中已有所描述。其變形係基於材料之微結構因 磁場而重新定向。變形的基礎係成雙的麻田散鐵 (m a r t e n s i t i c )微結構，該定向可被控制。麻田散鐵結構 係直接藉由鑄造技術及/或熱處理而達成。此外，為了使 變形能夠發生，材料必須具有磁性堅固性，在此情況下， 其晶格的磁向量必須不能比晶體晶格更容易轉換。如此内 部磁場可強力地維持既定的晶格定向，且當内部磁場轉換 時，晶格亦隨之轉換。 就磁激記憶金屬之觀點而言，重要的變量係麻田散鐵和 奥氏鐵（a u s t e n i t e )之相形成反應時的溫度，在此處相開 始形成（M s和A s )以及相形成結束（M f和A f )。此外，就 磁激記憶金屬之觀點而言重要的變量係居禮溫度T。。對於 鐵磁性材料（f e r r 〇 m a g n e t i c m a t e r i a 1 s )而言，居禮溫度係 一低於該溫度即會發生自發磁化反應的溫度，但高於該溫 312/發明說明書(補件)/92-08/92115658 1307367 度，該材料則為順磁性。藉由這些變量而從中定義出該材 料或合金的使用溫度。使用溫度係低於居禮溫度（必須是 鐵磁性材料），以及低於麻田散鐵反應的起始溫度（亦必須 是麻田散鐵材料）。就該材料之使用的觀點而言，該溫度係 儘可能地高較為有利，其可使得磁激記憶金屬的可用範圍 充分廣泛，以及允許例如因氣候條件或使用期間而對設備 力σ熱。 當一含有鎳、錳和鎵之記憶金屬（在本說明書以下對其 一般形式以NiMnGa表示）冷卻時，當在溫度範圍Mf 下冷卻時，奥氏鐵結構開始轉變成麻田散鐵結構，且當分 別以反向予以加熱時，則產生奥氏鐵A s A f。在N i Μ n G a 系統中，會產生不同的相，亦即，各種不同之順磁性和強 磁性形式之立方晶體和四面晶體相。在晶體結構和轉換溫 度之間其有所關聯。轉換溫度低於7 0 °C之合金具有一調製 (modulated)5層（5M)之四面晶體結構。7層斜方晶體 (orthorhombic )( 7M )結構亦可能在溫度範圍70°C -Tc 間出現。高於居禮溫度，結構則為未調製之四面晶體（T ) 麻田散鐵。 EP866142專利申請案係關於一種NiMnGa合金，尤其是 化學形式為NimMnuGa之該合金，其中參數x(莫耳數） 係選自0 · 1 0 S X S 0 . 3 0之範圍内。以此組成，麻田散鐵轉 換之最終溫度可選自介於-2 0 °C和7 0 °C之間的期望溫度， 而居禮溫度則可選自介於6.0 °C和8 5 °C之間的期望溫度。在 合金之記憶金屬特性中，有相關的是麻田散鐵轉換Ms— Mr 6 3 ] 2/發明說明書(補件)/92-08/92〗15658 1307367 和逆轉換As— At。描述於該EP專利申請案之NiMnGa合金 的典型特徵係，在麻田散鐵相之逆轉換係藉由一外部磁場 所達成，其結果則可恢復記憶。在該歐洲專利申請案EP 8 6 6，1 4 2中，描述如何製造已處理之N i Μ n G a合金，其係如 下：藉由混合合金組成分、以氬氣弧法熔化該混合物並將 其澆鑄成塊而製得N i Μ n G a合金鑄塊。之後將該鑄塊研磨成 N i Μ n G a合金粉末。該粉末經篩檢成大小低於2 5 0篩孔的顆 粒，並將其進一步壓密成直徑5毫米的棒狀物。該緊壓之 棒狀物在溫度8 0 (TC下燒結4 8小時。對於所得到之合金， 予以定義逆轉換之最終溫度A f和居禮溫度T。。因此，在根 據歐洲專利申請案E P 8 6 6 , 1 4 2製造合金時，例如，合金之 晶體結構或該晶體結構對記憶金屬性質之功效皆未被考慮 到。此外，在該歐洲專利申請案E P 8 6 6, 1 4 2之方法中，係 利用粉末冶金，其製造困難，且因而增加製造費用。 【發明内容】 本發明之目的係在於消除先前技術中之某些缺點，以及 實現一種改進方法，其在製造含有鎳、錳和鎵之磁激形狀 記憶金屬合金之操作中更為安全，使得對於該合金，可獲 得一有利於記憶金屬性質之晶體結構，以及可避免，例如， 粉末冶金之步驟。本發明之基本新穎特性被列述於隨附之 申請專利範圍中。 【實施方式】 藉由應用本發明之方法，其可以澆鑄而製造得一種含有 鎳、錳和鎵之磁激形狀記憶金屬合金，在該合金中，各種 7 312/發明說明書(補件)/92-08/92115658 1307367 不同組成分之含量可以改變，使得鎳含量係在4 5 - 6 0原子％ 之範圍内，锰含量係在1 5 - 3 5原子％之範圍内，鎵含量係在 1 5 - 3 0原子％之範圍内。在本方法中所使用之組成分首先予 以熔化並在控制之大氣環境和壓力下予以澆鑄，其基本上 可防止使合金組成分的揮發，且洗鑄物之組成可有利地均 勻製得。藉由澆鑄所獲得之所要的金屬合金可在低於該金 屬合金之相平衡圖之液體溫度以下之1 0 5 0 - 1 2 0 0 °C ，較有 利的是1 1 2 0 - 1 1 7 0 °C之溫度範圍内，藉由方向性凝固而予 以固化，在該情況下，金屬合金之晶體結構變成方向性組 織結構，其對於磁激記憶金屬之最大伸展性而言係很重要 的。 根據本發明，為了產生金屬合金，含於合金中之鎳、錳 和鎵被承載，較佳係以N i - Μ η及/或N i - G a主合金，以及 其精密性藉由純金屬來達成。主合金可被有利地製成使得 最底的材料為具有最低熔點溫度（3 0 °C )的鎵，在其上則 為錳（1 2 4 6 °C )以及最頂端為鎳（1 4 5 5 °C )。主合金之熔點 較佳係在溫度1 5 0 0 °C下誘導進行，在該溫度下保持熔融物 約_ 1小時，以均質化該合金，之後將其冷卻並碾碎成適於 坩堝的小塊。該金屬合金本身，N i Μ n G a，係較有利地製成 使得在底部之最底下者為精密金屬，以及其頂端為主合金 或合金。熔化在溫度1 3 0 0 °C下誘導進行較佳，在該溫度下 熔融物被保持約1小時，以均質化該合金。金屬合金N i Μ n G a 的澆鑄係在溫度約1 1 8 0 °C下進行，而方向性凝固之鎔爐的 溫度約1 1 3 0 °C較為有利。揮發性組成分諸如錳和鎵的蒸發 8 312/發明說明書(補件)/92-08/92115658 1307367 係藉由在錄爐中調整次壓力在範圍20-200毫巴（mbar)内 而受到控制。 於本發明之製法中所得到之澆鑄物係在溫度8 0 0 - 1 0 0 0 °C範圍内之保護性氣體環境中被均質化，在該溫度範圍 中，含於鎳-I孟-鎵合金中所謂郝斯勒（H e u s 1 e r )相的穩定 區域以較大為佳。其所使用之保護性氣體例如氬氣、氮氣 或其組合較為有利。 以本發明之方法所得到之洗鑄件的凝固以在低於金屬 合金之液態溫度的1 0 - 1 0 0 °C下進行較為有利。澆鑄件的凝 固速率係在0 . 1 - 5 0毫米/分，以1 - 2 0毫米/分的範圍較 佳。在凝固程序中，較有利者係使用一實質上在標準條件 下的溫度梯度鎔爐，在該鎔爐中，熱基本上係被引導遠離 澆鑄製模的長度方向。如此凝固溫度係以基本上均勻的方 式而改變，且所得之固化金屬合金的晶體結構係為方向性 組織結構。方向性凝固的結果，可達到一牢固的各向異性 澆鑄件，而機械性脆弱之細粒邊緣係設定在澆鑄件的長度 方向。因此，舉例而言，澆鑄件的強度性質在不同方向上 係不相同的。 對根據本發明之方法所製造之金屬合金，測量其麻田散 鐵和奥氏鐵反應的起始溫度（M s、A s )和最終溫度（M r、 A f )以及居禮溫度（T。）。測量結果如下表所示： 9 312/發明說明書(補件)/92-08/92115658 1307367 合金 N i (%) Mn(%) Ga(%) Ms°C Mr°C As°C At°C Tc°C 1 49. 6 28. 4 22 33 31 37 40 99 2 48. 5 30. 3 21. 2 28. 5 26 32 35 99 3 48. 4 31. 1 20. 5 34 32 42 45 97 4 50.7 27.8 21.5 52 50 58 61 98 5 48.9 30. 8 20. 3 51.3 48 58. 5 62 96. 8 6 49. 9 29. 9 20.2 70. 6 65 76. 7 81. 1 95. 7 7 50.5 29. 4 20. 1 78.6 68. 4 75.4 86 93 由表中可見，金屬合金的居禮溫度係顯著地高於室溫， 其表示在室溫下，所製得的金屬合金具有強磁性（鐵磁 性）。對於部分表中所列的合金，麻田散鐵反應之轉換溫度 係接近於室溫，奥氏鐵反應之溫度亦如是。因此麻田散鐵 反應實質上係於室溫下發生，而該合金為所謂的室溫合 金。藉由調整組成和結構，可得到所謂的高溫合金，其轉 換溫度係在5 0 - 8 0 °C範圍内，且操作區域範圍自一低溫直 至轉換溫度。表中所列的合金大部分係該高溫合金。 根據本發明之方法所製得之合金亦接受伸展和彎折實 驗。於室温下測量的伸展最佳的係四面晶體5M結構6%， 以及斜方晶體7 Μ結構1 0 %。 10 312/發明說明書(補件)/92-08/921156581307367 发明Invention Description: [Technical Field] The present invention relates to a method for producing a shape memory metal alloy containing nickel, manganese and gallium by casting, applying directional solidification, which makes the shape The crystal structure of the memory metal alloy achieves greater crystallization and has the desired directionality. [Prior Art] A magnetic or magnetron metal is a material that allows a member made therefrom to be reshaped under control - it is wound, stretched, and bent by the action of an external, adjustable magnetic field. The properties of memory metals are described, for example, in Finnish Patent No. 1,0 1,5,633. The deformation is based on the microstructure of the material being redirected by the magnetic field. The basis of the deformation is a double microstructure of the mascara (m a r t e n s i t i c ), which orientation can be controlled. The granulated iron structure is achieved directly by casting techniques and/or heat treatment. Furthermore, in order for deformation to occur, the material must be magnetically robust, in which case the magnetic vector of its lattice must not be easier to convert than the crystal lattice. Such an internal magnetic field can strongly maintain a predetermined lattice orientation, and when the internal magnetic field is switched, the crystal lattice also changes. From the point of view of the magnetic memory metal, the important variable is the temperature at which the phase of the granulated iron and the austenite phase react, where the phase begins to form (M s and A s ) and the phase formation ends ( M f and A f ). Further, the variable important in terms of the magnetic memory metal is the Curie temperature T. . For ferromagnetic materials (ferr mamagneticmateria 1 s ), the temperature at which the Curie temperature is below this temperature will occur at a temperature below the temperature, but above the temperature 312 / invention specification (supplement) / 92-08 / 92115658 1307367 degrees, the material is paramagnetic. The temperature at which the material or alloy is used is defined by these variables. The temperature used is below the ambient temperature (must be ferromagnetic) and below the onset temperature of the granulated iron (which must also be a granulated iron material). From the standpoint of the use of the material, it is advantageous that the temperature is as high as possible, which makes the usable range of the magnetically active memory metal sufficiently broad, and allows the device to be thermally heated, for example, due to climatic conditions or periods of use. When a memory metal containing nickel, manganese and gallium (represented by NiMnGa in the general form below this specification) is cooled, when cooled in the temperature range Mf, the austenitic iron structure begins to transform into a granulated iron structure, and when When heated in the opposite direction, austenite A s A f is produced. In the N i Μ n G a system, different phases, i.e., various cubic and tetragonal crystal phases of paramagnetic and ferromagnetic forms are produced. It is related between the crystal structure and the transition temperature. An alloy having a switching temperature lower than 70 °C has a modulated five-layer (5M) four-sided crystal structure. The 7-layer orthohombic (7M) structure may also occur between 70 °C and Tc. Above the Curie temperature, the structure is unmodulated four-sided crystal (T) 麻田散铁. The EP 866 142 patent application relates to a NiMnGa alloy, especially the alloy of the chemical form NimMnuGa, wherein the parameter x (mole number) is selected from the range of 0 · 1 0 S X S 0 . In this way, the final temperature of the transition of the granulated iron can be selected from the desired temperature between -2 °C and 70 °C, while the temperature of the ritual can be selected from 6.0 °C and 85 °C. The desired temperature between. Among the alloy metal properties of the alloy, there is related to the Ma Tian loose iron conversion Ms— Mr 6 3 ] 2 / invention specification (supplement) / 92-08/92〗 15658 1307367 and inverse conversion As-At. The typical characteristic of the NiMnGa alloy described in the EP patent application is that the inverse transformation of the iron phase in the field is achieved by an external magnetic field, and as a result, the memory can be restored. In the European patent application EP 8 6 6 141, how to make a treated N i Μ n G a alloy is prepared as follows: by mixing the alloy composition, the mixture is melted by argon arc method and It was cast into a block to obtain an N i Μ n G a alloy ingot. The ingot was then ground into a N i Μ n G a alloy powder. The powder was sieved into particles having a size below 250 mm and further compacted into rods having a diameter of 5 mm. The pressed rod is sintered at a temperature of 80 (TC) for 48 hours. For the obtained alloy, the final temperature Af of the reverse conversion and the Curie temperature T are defined. Therefore, in accordance with the European Patent Application EP 8 6 6 , 1 4 2 When manufacturing an alloy, for example, the crystal structure of the alloy or the effect of the crystal structure on the properties of the memory metal is not taken into account. Furthermore, in the European patent application EP 8 6 6 1 4 2 In the method, powder metallurgy is used, which is difficult to manufacture, and thus increases manufacturing costs. SUMMARY OF THE INVENTION The object of the present invention is to eliminate some of the disadvantages of the prior art and to achieve an improved method for producing nickel and manganese. It is safer to operate with a magnetically excited shape memory metal alloy of gallium, so that a crystal structure which is advantageous for the memory metal property can be obtained for the alloy, and steps such as powder metallurgy can be avoided. Basic novel characteristics of the present invention It is listed in the scope of the accompanying patent application. [Embodiment] By applying the method of the present invention, it can be cast to produce a nickel, manganese and gallium containing Excited shape memory metal alloy in which various 7 312 / invention instructions (supplement) / 92-08/92115658 1307367 different composition content can be changed, so that the nickel content is in the range of 4 5 - 60 atomic % The manganese content is in the range of 15 - 35 atomic % and the gallium content is in the range of 1 5 - 30 atomic %. The components used in the method are first melted and controlled in the atmosphere. And casting under pressure, which substantially prevents volatilization of the alloy component, and the composition of the casting can be advantageously uniformly obtained. The desired metal alloy obtained by casting can be lower than the phase of the metal alloy. 1 0 5 0 - 1 2 0 0 °C below the liquid temperature of the equilibrium diagram, more advantageously in the temperature range of 1 1 2 0 - 1 1 7 ° ° C, solidified by directional solidification, In this case, the crystal structure of the metal alloy becomes a directional structure, which is important for the maximum extensibility of the magnetic memory metal. According to the present invention, nickel, manganese and gallium contained in the alloy are produced in order to produce a metal alloy. Being carried, preferably with N i - Μ η and / or N i - G a main alloy, and its precision is achieved by pure metal. The main alloy can be advantageously made such that the lowest material has the lowest melting point temperature (30 ° C) Gallium, on which is manganese (1 2 4 6 ° C) and the topmost is nickel (1 4 5 5 ° C). The melting point of the main alloy is preferably induced at a temperature of 1 500 ° C, The melt is held at this temperature for about _1 hour to homogenize the alloy, which is then cooled and crushed into small pieces suitable for the crucible. The metal alloy itself, N i Μ n G a , is advantageously formed The bottom of the bottom is made of precision metal, and its top is dominated by alloys or alloys. The melting is preferably carried out at a temperature of 130 ° C at which the melt is held for about 1 hour to homogenize the alloy. The casting of the metal alloy N i Μ n G a is carried out at a temperature of about 1 18 ° C, and the temperature of the directional solidification furnace is about 1 130 ° C. Evaporation of volatile components such as manganese and gallium 8 312 / invention specification (supplement) / 92-08/92115658 1307367 is controlled by adjusting the secondary pressure in the recording furnace in the range of 20-200 mbar . The casting obtained in the process of the present invention is homogenized in a protective gas atmosphere in the temperature range of 80 - 1 0 0 ° C, and is contained in the nickel-I-monium-gallium in this temperature range. The stable region of the so-called Heusler phase in the alloy is preferably larger. It is advantageous to use a protective gas such as argon, nitrogen or a combination thereof. The solidification of the casting obtained by the method of the present invention is advantageously carried out at a temperature lower than the liquid temperature of the metal alloy at 10 to 100 °C. The solidification rate of the casting is preferably from 0.1 to 50 mm/min, preferably from 1 to 20 mm/min. In the solidification procedure, it is advantageous to use a temperature gradient crucible that is substantially under standard conditions in which heat is substantially directed away from the length of the casting mold. The solidification temperature is thus changed in a substantially uniform manner, and the crystal structure of the resulting solidified metal alloy is a directional structure. As a result of the directional solidification, a strong anisotropic casting can be achieved, and the mechanically fragile fine grain edge is set in the length direction of the casting. Thus, for example, the strength properties of the castings are different in different directions. For the metal alloy produced by the method according to the invention, the initial temperature (M s, A s ) and the final temperature (M r, A f ) of the reaction between the granulated iron and the austenite iron and the temperature of the ritual (T. ). The measurement results are shown in the following table: 9 312/Invention Manual (Supplement)/92-08/92115658 1307367 Alloy N i (%) Mn(%) Ga(%) Ms°C Mr°C As°C At°C Tc °C 1 49. 6 28. 4 22 33 31 37 40 99 2 48. 5 30. 3 21. 2 28. 5 26 32 35 99 3 48. 4 31. 1 20. 5 34 32 42 45 97 4 50.7 27.8 21.5 52 50 58 61 98 5 48.9 30. 8 20. 3 51.3 48 58. 5 62 96. 8 6 49. 9 29. 9 20.2 70. 6 65 76. 7 81. 1 95. 7 7 50.5 29. 4 20 1 78.6 68. 4 75.4 86 93 It can be seen from the table that the salient temperature of the metal alloy is significantly higher than room temperature, which means that the metal alloy produced has strong magnetic properties (ferromagnetic) at room temperature. For the alloys listed in the table, the transition temperature of the granulated iron reaction is close to room temperature, and the temperature of the austenite reaction is also the same. Therefore, the 麻田散铁 reaction occurs substantially at room temperature, and the alloy is a so-called room temperature alloy. By adjusting the composition and structure, a so-called superalloy can be obtained with a conversion temperature in the range of 50 - 80 °C and an operating range ranging from a low temperature to a switching temperature. Most of the alloys listed in the table are the superalloys. Alloys made in accordance with the method of the present invention also undergo extension and bending experiments. The optimum stretch of the four-sided crystal 5M structure measured at room temperature was 6%, and the orthorhombic crystal 7 Μ structure was 10%. 10 312/Invention Manual (supplement)/92-08/92115658