Preparation and Characterization of Dual-Amorphous-Phased Bulk Metallic Glass Composites Formed by Powder Metallurgy Route

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Project title

Code/計畫編號

NSC97-2221-E019-005-MY3

Translated Name/計畫中文名

雙非晶質相金屬玻璃複合材料之粉末冶金製程與特性研究

Project Coordinator/計畫主持人

Pee-Yew Lee

Funding Organization/主管機關

National Science and Technology Council

Department/Unit

Department of Optoelectronics and Materials Technology

Website

https://www.grb.gov.tw/search/planDetail?id=1987403

Year

2010

Start date/計畫起

01-08-2010

Expected Completion/計畫迄

31-07-2011

Bugetid/研究經費

1131千元

ResearchField/研究領域

材料科技

"近年來由許多學者對塊狀金屬玻璃(Bulk Metallic glasses ; BMGs)所做的研究顯示，BMGs 相較於傳統的結晶材料，雖具有較高的彈性限及強度，但當 BMGs 遭受破壞時，材料內部無晶界等來阻擋剪變帶的移動，因此容易導致剪變帶快速通過，並瞬間造成材料破裂，故BMGs 就實質上而言，是一種不具延展性的脆性材料；所幸此缺失可藉由在BMGs 基材上添加第二強化相形成 BMGs 複合材料而獲得改良，但是對於在BMGs 中添加第二相為玻璃相，藉此合成非晶質相/非晶質相的雙相BMGs 複合材料之研究，經文獻調查後發現，僅有少數學者以熔煉鑄造的方式進行，然而以鑄造的方式製備雙相BMGs 複合材料時，所選取的合金組成須具有兩項性質: (1) 在溶融液態時具有雙重液相分離特徵以形成兩種成份不同的液相結構，(2) 此兩種液相結構須具有非晶質相形成能力以利於在冷卻凝固過程時形成非晶質結構，但具此種特性的合金又非常稀少，因此嚴重降低以鑄造方式製備雙相非晶質合金的可行性；相對於此，若以粉末冶金的方式，將任何兩種已具非晶質相的粉末，經由粉末混合及成型的過程，將可能比前述的鑄造方式更容易製備出雙相BMGs 複合材料。綜上所述，本研究之目的在探討利用粉末冶金製程來製備雙非晶質相複合材料塊材之可行性，研究工作之進行先利用機械合金法（Mechanical Alloying, MA）分別製備出Ti50Cu28Ni15Sn7 與Ni60Nb20Zr20 兩種非晶質合金粉末，將此兩種非晶質相粉末再以高能量球磨機球磨均勻混合成雙非晶質相複合材料粉末後，最後利用真空熱壓成型技術將此複合材料粉末製備成雙相非晶質合金塊材，所製備之雙相非晶質複合材料除以DSC、XRD、SEM、TEM 分析其結構與特性外，另亦針對雙相非晶質合金塊材進行壓縮試驗，以及在不同水溶液環境下的動態極化試驗，藉此瞭解Ti50Cu28Ni15Sn7 /Ni60Nb20Zr20 雙相非晶質合金塊材的機械性質與抗蝕能力，由於研究範圍頗廣，一年內無法完成所有的實驗工作，故本計畫將以三年的時間進行, 第一年先進行機械合金法合成 Ti50Cu28Ni15Sn7 /Ni60Nb20Zr20 雙非晶質相複合材料粉末工作，並以X-ray、SEM、和DSC 檢測球磨粉末的結構及相關特性，以瞭解應用機械合金法製造雙非晶質相複合材料粉末的功效，第二年則進行雙非晶質相複合材料塊材之真空熱壓成型製備工作，所製造之塊材亦利用X-ray、SEM、DSC、TEM 進行結構及相關特性之量測，第三年之工作重點則針對雙相非晶質合金塊材進行壓縮試驗以及在不同水溶液環境下的動態極化試驗，藉此瞭解Ti50Cu28Ni15Sn7 /Ni60Nb20Zr20雙相非晶質合金塊材的機械性質與抗蝕能力；詳細評估三年工作所得之數據資料後，將可獲知結合機械合金法及真空熱壓製程之粉末冶金途徑製備塊狀雙非晶質相複合材料塊材的最佳化條件。""Bulk metallic glasses (BMGs) have shown superior properties such as high strength, low Young’s modulus and largeelastic limit. However, the BMGs usually show little overall room temperature plasticity due to the formation of highly localized shear banding, resulting in a catastrophic failure. One way to overcome this problem is to produce the composite materials containing crystalline phase. Attempts have been made to enhance the ductility of BMGs by introducing crystalline phase into the metallic glass matrix by partial devitrification, adding particle or fibers during casting or consolidation process, and in-situ formed ductile phase precipitates. It was found that the plastic deformation of monolithic BMGs could be enhanced by adding some crystalline phase into the metallic glass matrix composites (MGMCs). This deformation behavior in MGMCs is achieved by the formation of multiple shear bands initiated at the interface between the reinforcing phase and the metallic glass matrix. In an effort to further improve the properties of MGMCs, a new kind of dual-amorphous-phased bulk metallic glass (DAPBMG), which consists of two amorphous phases, has attracted increase R&D interest. Similar to a composite material, the dual-amorphous-phased BMG can be expected to exhibit the properties of both its original constituents. For instance, the relatively brittle Fe-based BMG can be improved by alloying it with high-toughness Zr-based BMG. The requirements for the formation of dual-amorphous-phased BMG are phase separation into two different liquid phases structure at melting state and the high glass-forming ability of the liquid phase during cooling. Unfortunately, the alloys with confined constitutional range that can induce phase separation are very rare and thus only little progress has been made for the preparation of dual-amorphous-phased BMG by using conventional casting or mold injection techniques. Therefore, an alternative technique to prepare bulk dual-amorphous-phased alloys would be via powder metallurgical methods, where the amorphous alloy can be prepared individually and then consolidated into a disc by hot pressing or other appropriate processes. Consequently, the aim of this project is to investigate the feasibility of preparing new (Ti50Cu28Ni15Sn7)100-x(Ni60Nb20Zr20)x dual-amorphous-phased BMG by a combination of mechanical alloying (MA) and vacuum hot-pressing techniques. A high-energy ball mill will be employed to produce mechanically alloyed Ti50Cu28Ni15Sn7 and Ni60Nb20Zr20 amorphous powders. The (Ti50Cu28Ni15Sn7)100-x(Ni60Nb20Zr20)x dual-amorphous-phased composite powders will then be prepared by mixing the Ti50Cu28Ni15Sn7 and Ni60Nb20Zr20 amorphous powders using same ball mill. The successfully prepared dual-amorphous-phased composite powders with wide supercooled liquid region will be consolidated into bulk forms by using a uniaxial hot press machine. The structure and selected properties of as-prepared powders and dual-amorphous-phased BMG will be examined by X-ray diffraction, scanning electron microscopy, transmission electron microscopy and by using a differential scanning calorimeter. In addition, both the compression and anodic polarization tests on the dual-amorphous-phased BMG will be conducted in order to understand the mechanical property and corrosion resistance of dual-amorphous-phased BMG. The whole program will be carried out in three years after careful consideration of experimental works. The main goal in the first year is to prepare and evaluate the (Ti50Cu28Ni15Sn7)100-x(Ni60Nb20Zr20)x dual-amorphous-phased composite powders formed by mechanical alloying process. In the second year, the major work will be the preparation of dual-amorphous-phased BMG by consolidating dual-amorphous-phased composite powders into bulk forms by using a uniaxial hot press machine. The experimental work in the third year will be focused on the examination of mechanical properties and corrosion resistance of dual-amorphous-phased BMG by performing compression and anodic polarization tests. After comprehensive evaluation of all the experimental results obtained in this work, the optimum conditions for the production of dual-amorphous-phased BMG through powder metallurgy route."

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Preparation and Characterization of Dual-Amorphous-Phased Bulk Metallic Glass Composites Formed by Powder Metallurgy Route

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