A D V A N C E D M A T E R I A L S & P R O C E S S E S | J A N U A R Y / F E B R U A R Y 2 0 2 3 3 7 substructure, microstructure, and microstructural distribution; intermetallic and precipitation carbide strengthening; and substantially reduced cobalt content compared to alloy J3 and J10. The nominal composition of the five VSI alloys included in Fig. 1 are summarized in Table 1. WEAR RESISTANCE One of the challenges for traditional VSI alloys (e.g., J3, J10, and J100) in terms of wear resistance involves their relative soft matrix (cobalt or nickel solid-solution phase). Under a high pressure and temperature engine combustion condition, the soft phase can deform, thus strengthening hard phases such as primary carbides (J3 and J100) and Laves-phase compounds (J10) can be ruptured under impacting and sliding motions. The ruptured primary carbide or Laves phase then becomes part of a tribosystem and causes severe abrasive wear. The J513 solidification substructure includes cellular/cellular dendritic types, in contrast to columnar dendritic/cellular dendritic types for J3, J10, and J100. As a result, J513 microstructure is much finer and the different phases are more uniformly distributed in its matrix compared to J3, J10, and J100. This is one of the factors that impacts improved and consistent wear resistance. Figure 2 shows the typical microstructure of the five alloys listed in Table 1. With the alloy design concept, a good compressive yield strength has been achieved in J513. Compressive yield is one of the key material properties affecting the wear resistance of high-temperature materials. Figure 3 illustrates a comparison of compressive yield strength for J3, J10, and J513. CONCLUSION The excellent performance of J513 alloy has been observed in more than six years of field engine experience with a wide range of engines, confirming the effectiveness of the J513 alloy design concept. Compared to conventional J3 and J10 cobalt-based alloys, J513 is not only a cost reduction and higher performance solution for diesel and natural gas engine applications but also is a sustainable materials engineering solution with substantially less cobalt usage. ~AM&P For more information: C. Paul Qiao, vice president—metallurgy and R&D, L.E. Jones Company Inc., 1200 34thAve., Menominee, MI 49858, 906.863.4411, pqiao@lejones.com. References 1. Welding, Brazing and Soldering, Vol. 6, ASM Handbook, ASM International, 1993. 2. Surface Engineering, Vol. 5, ASM Handbook, ASM International, 1994. 3. Materials Characterization, Vol. 10, ASM Handbook, ASM International, 2019. Fig. 3 — Compressive yield strength as a function of test temperature. Fig. 2 — Typical microstructures: (a) J3; (b) J10; (c) J160; (d) J100; and (e) J513. All images 100X. (a) (b) (c) (d) (e)
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