SiCp/17-4PH不銹鋼複合合金之製備、微結構及機械性質之研究

Investigation of Procedure, Microstructure and Mechanical Properties on SiCp/17-4PH stainless steel composite alloy

林依正(Yi-Cheng Lin)

指導教授 ： 徐開鴻

國立臺北科技大學/工程學院/材料科學與工程研究所/碩士(2011年)

摘要

本研究探討以17-4PH( AISI 630)不銹鋼粉為基材，添加7-21vol.%SiC(6H-SiC)粉，於大氣氣氛下經攪磨處理，製備SiC顆粒強化17-4PH不銹鋼之複合粉，並以熱壓(Hot Pressing)的方式在850、900、950及1000℃，壓力固定為60 MPa，持溫時間為1 h進行燒結成形，接著再依據850及1000℃的熱壓條件之各組試片分別施予9、18次與6、15次製程循環之熱鍛處理(1050℃)，使複合合金的緻密性提升，完成SiC顆粒強化17-4PH不銹鋼複合合金。
實驗結果顯示，在BPR 80:1、570 rpm、5 hr的攪磨條件下，可得到最佳的SiCp/17-4PH不銹鋼複合粉。經(1000℃、60 MPa)熱壓成形後的試片，施予一結合熱能與塑性變形的熱鍛之處理程序可有效使其相對密度、硬度與橫向壓裂強度等相關性質的提升，其中以15次製程循環之相對密度可達98~99%，而在此熱壓-熱鍛條件下所得之橫向壓裂強度(TRS)方面，以添加7vol.%SiCp的複合合金TRS最高，約為1604.52 MPa(232.78×103 psi)；在硬度方面，則以添加21vol.%SiCp之複合合金具有最高硬度，硬度值為HRA 86.2(相當於HRC 69.4)，橫向壓裂強度值為1433.64 MPa(207.99×103 psi)；而在顯微組織方面，由於熱壓成形後再經一熱鍛處理，複合合金本身則會因成形加工的過程不斷地發生塑性變形之影響，造成分佈於粒界間之SiCp可更為均勻散佈在17-4PH不銹鋼基材內，因此在機械性質方面可媲美市面上之Ferro-TiC®(CS-40，45vol.%TiC、HRC 68、TRS 149×103 psi)。

關鍵字

機械合金法 ； 單軸熱壓 ； 熱鍛處理 ； SiC顆粒 ； 17-4PH不銹鋼 ； 複合合金

並列摘要

In this study, 17-4PH stainless steel with different contains (7, 11 and 21 vol.%) for silicon carbide are used for preparing SiC particulate reinforced 17-4PH stainless steel composite powder though attrition milling at an air atmosphere. The mixed composite powder were hot pressed at 850、900、950、1000℃ and 60 MPa for 1 hour, followed at 850℃ and 1000℃ according to the hot pressing conditions, lend specimens were 9、18 times and 6、15 times of process cycle for hot forging, improved the densification of composite alloy, and completed SiC particulate reinforced 17-4PH stainless steel composite alloy.
The results show that uniformly mixed SiCp/17-4PH stainless steel carbide particulate strengthened composite powder is obtained by BPR 80:1 and rotating speed 570rpm for attrition milling. The mixed composite powders were hot pressed at 1000℃ and 60 MPa, followed by a combination of heat and plastic deformation of hot forging process can effectively make the relative density, hardness and bending strength related properties such as the upgrading, which the process by 15 cycle of relative density for up to 98~99%. In this condition show that a high TRS value of 1604.52 MPa (232.78×103 psi) was obtained when the 7vol.%SiCp composite alloy. The 21vol.%SiCp composite powder had the highest hardness (HRA 86.2 or HRC 69.4) and TRS 1433.64 MPa (207.99×103 psi) after hot pressed at 1000℃, followed by hot forging process (process cycle of 15 times). The microstructural evaluation revealed that a result of composite powders after hot pressed, followed by a series of hot forging process, composite alloy was due to effect of molding process for caused continuous plastic deformation, resulting in SiC particulate uniformly dispersioned in 17-4PH stainless steel matrix. The mechanical properties result were better than those reported for Ferro-TiC®(CS-40，45vol.%TiC、HRC 68、TRS 149×103 psi).

並列關鍵字

Mechanical Alloying ； Hot Pressing ； Hot forging process ； SiC particulate ； 17-4PH stainless steel ； Composite alloy

參考文獻

[3] Zdzislaw Klim, Elmekki Ennajimi, Marek Balazinski, and Clement ortin, "Cutting Tool Reliability Analysis for Varible Feed Miling of 17-4PH Stainless Steel", Wear, vol. 195, 1996, pp. 6-213.

[6] "Carpenter Precipitation Hardening Stainless Steels", Manufacturer’s Product Bulletin, Carpenter Technology Co., PA, 1986.

[7] C. C. Koch and J.D. Whittenberger, "Mechanical milling / alloying of intermetallics," Intermetallics, vol. 4, 1996, pp.339-355.

[8] C. Suryanarayana, "Mechanical alloying and milling," Progress in Materials Science, vol.46, 2001, pp. 1-184.

[9] C. Suryanarayana, E. Ivanov and V. V. Boldyrev, "The Science and Technology of Mechanical Alloying," Materials Science and Engineering A,304-306, 2001, pp.151-158.