真空燒結法對鈦銅鉬合金添加不同碳化物之顯微組織與強化機制探討

鈦合金發展至今已有200餘年歷史，其優異的物理、抗腐蝕與生醫相容性，可應用於航太與生醫材料上。鈦合金的粉末冶金產品通常會導致比其它製造方式的相對密度和強度來得低，故改善粉末冶金製造的鈦合金性質，變成相當地重要。本實驗利用鈦粉、銅粉與鉬粉三種不同金屬粉末，經由混合後製造出鈦銅鉬合金，其分別為: Ti-6Cu-8Mo, Ti-9Cu-8Mo與Ti-12Cu-8Mo三種不同配比；此外，鈦銅鉬合金並於1150°C、1175°C與1200°C三種溫度下進行真空燒結。為評估經由真空燒結製程的鈦銅鉬合金之組織與機械性質，本實驗利用燒結密度、硬度、橫向破裂強度(TRS)，以及XRD與SEM等方式判斷其性質之優劣。同時為改善燒結鈦銅鉬合金之微結構與性質，研究中將最佳的燒結合金參數，添加不同的碳化物(WC, TaC與ZrC)以做為強化相之改良。實驗結果顯示Ti-12Cu-8Mo合金於1200°C燒結下，可得到較高之密度(94.7%)、硬度(38.79 HRC)與橫向破裂強度(1204 MPa)，其主要為提升銅的含量，可以有效改善及抑制孔洞成長。而在添加碳化物的部分，以添加5 wt%碳化鋯(ZrC)具有較佳的效果，其燒結密度(98%)、硬度(45.13 HRC)與橫向破裂強度(1068 MPa) 都可以明顯地提高；然而由於晶界缺陷的影響，將使添加5 wt% ZrC的鈦銅鉬合金(Ti-12Cu-8Mo)之抗蝕性下降。

關鍵字

粉末冶金；鈦銅鉬合金；真空燒結；橫向破裂強度；碳化鋯

並列摘要

Titanium alloys have been developed and applied in the last 200 years, which exhibit unique physical properties, corrosion resistance and biocompatibility, mostly applied to aerospace and biomedical materials. Powder Metallurgy (P/M) of titanium and its alloys may lead to relative density and strength lower than that from common processes. For this reason, improving the P/M of titanium alloy properties becomes more important. In this study, three different powders were mixed and used to produce Ti-Cu-Mo alloys. It contains three kinds of proportions: Ti-6Cu-8Mo, Ti-9Cu-8Mo and Ti-12Cu-8Mo, respectively. In addition, the Ti-Cu-Mo alloys underwent a vacuum sintering process in which the sintering temperatures were 1150°C, 1175°C and 1200°C. To evaluate the microstructure and mechanical properties of the Ti-Cu-Mo alloys via vacuum sintering processes sintering density, hardness and transverse rupture strength (TRS), XRD, SEM and microstructure inspections were performed. Moreover, this was used to improve the microstructure and properties of sintered Ti-Cu-Mo alloys. All of the optimally sintered specimens were subjected to various added carbides (WC, TaC and ZrC) after the vacuum sintering process. The experimental results showed that a higher density (94.7%), hardness (38.79 HRC) and transverse rupture strength (1204 MPa) for Ti-12Cu-8Mo alloys were obtained after 1200°C vacuum sintering. This indicates that owing to the pores existing in the sintered Ti-Cu-Mo alloys the alloys can be effectively improved and inhibited by adding more copper content. Furthermore, adding 5 wt% ZrC carbide to Ti-12Cu-8Mo alloys creates optimal properties. Meanwhile, the sintered density was obviously increased to about 98%, hardness, the HRC was enhanced to 45.13 and the TRS increased to 1068 MPa, respectively. However, the influence of grain boundary defects result in a decrease in corrosion resistance of Ti-12Cu-8Mo alloys (5 wt% ZrC).

並列關鍵字

Powder Metallurgy ； Ti-Cu-Mo alloys ； vacuum sintering ； TRS ； ZrC

參考文獻

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真空燒結法對鈦銅鉬合金添加不同碳化物之顯微組織與強化機制探討

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