包埋材快速加熱下純鈦及鎳鉻合金鑄造物之機械性質

Mechanical properties of titanium and Ni-Cr alloy casting obtained from commercial investment with quick-heating

楊弘華(Hung-Hua Yang)

指導教授 ： 燕敏

中山醫學大學/口腔醫學院/口腔材料科學研究所/碩士(2005年)

摘要

最近的報告指出應用部分市售鈦包埋材以及快速加熱型磷酸鹽系包埋材可以實施快速加熱鑄造技術，其包埋材的物理性質和鑄造性與應用傳統的鑄造方式之結果相同，但是應用這種快速加熱鑄造技術對於鈦及鎳鉻合金鑄造物的機械性質的影響尚不十分清楚。本研究的目的為探討包埋材料經快速加熱處理，對鈦及鎳鉻合金鑄造物的機械性質之影響。
實驗選用兩種市售鈦專用包埋材和四種磷酸鹽系包埋材，實驗用試片採用棒狀啞鈴型，包埋材料的加熱方式為傳統與快速加熱方式。試片經鑄造程序之後，分別測量鈦及鎳鉻合金鑄件的抗拉強度，降伏強度，彈性模數跟伸長百分率及微硬度，之後使用光學顯微鏡及掃描式電子顯微鏡觀察鑄造物橫斷面表面反應層結構以及拉伸試驗後破斷面的顯微結構。
結果顯示各種包埋材經快速加熱鑄造之純鈦及鎳鉻合金鑄造物的機械性質及微硬度與傳統方式的結果在統計學上均沒有差異(p＞0.05)，而在不同包埋材中Tancovest的鈦鑄造物的抗拉強度明顯高於Rematitan Plus的鑄造物，以及Fujivest的鎳鉻合金鑄造物的伸長百分率明顯大於Maruvest的鑄造物（p＜0.05），包埋材廠牌的不同是造成以上差異的主因。不同包埋材所得的鈦及鎳鉻合金鑄造物微硬度無顯著差異。應用Rematitan Plus所得鈦鑄造物的表面反應層約100 μm，Tancovest的表面反應層約150 μm，且不同加熱方式對所得的表面反應層厚度沒有改變。
結論：實驗證明包埋材料以快速加熱方式不會影響鈦鎳鉻合金鑄造物之機械性質。

關鍵字

機械性質 ； 鈦 ； 鎳鉻合金 ； 包埋材 ； 快速加熱 ； 表面反應層

並列摘要

Currently, the commercial quick-heating phosphate-boned investments have been used for accelerated casting applications. The previous reports indicated that the possibility of a quick-heating method (QHM) for several conventional investments designed for titanium dental castings. The finding suggested that the properties and castability of the investment for titanium with QHM was not significantly different from that of the investment with conventiona-heating method（CHM）. However, the mechanical properties of titanium and Ni-Cr alloy casting using the investments with different burnout methods were not clearly examined. The purpose of this study was to investigate the mechanical properties of titanium and Ni-Cr alloy casting obtained from the investments with QHM. The dumbbell-shaped cp Ti and Ni-Cr alloy castings were fabricated using two commercial investments for titanium and four commercial phosphate-bonded investments for Ni-Cr alloy. The burnout process was performed by quick-heating method and the conventional method. The tensile strength, yield strength, elastic modulus and the percentage of elongation of titanium and Ni-Cr alloy castings were measured using a universal testing machine. The micro Vickers hardness (Hv) was measured at the surface of the sectioned each casting, and then to observe the structure of surface reaction layer with an optical microscope. The microstructure of fracture surface after tensile test was examined by SEM. Two-way ANOVA and Tukey comparisons were used for statistical evaluation (P = 0.05). The tensile strength of Tancovest showed significantly greater than that of Rematian （p＜0.05）, while the elongations of Fujivest were greater than that of Maruvest. However, the heating method, QHM or CHM, was not significant for mechanical properties and hardness value of titanium and Ni-Cr alloy specimens. On the contrary, the brand of the investment as main factor was significant for tensile strength and percentage of elongation of titanium and parts of Ni-Cr alloy specimens. Hardness value did not significantly change from 150 µm for Tancovest and 100 µm for Rematitan. These surface reaction layer thicknesses did no change between two heating methods. These results suggest that the quick heating method does not influence on the mechanical properties of the titanium and Ni-Cr alloy casting obtained from these examined commercial investments.

並列關鍵字

Mechanical properties ； titanium ； nickel-chromium alloy ； investment ； quick heating method ； surface reaction layer

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