Microstructures and Properties of 17-4 PH Stainless Steel Fabricated by Selective Laser Melting

By L. Murr, E. Martinez, Jennifer Hernandez, S. Collins, K. Amato, S. Gaytan, P. Shindo. 2012

368 citations recorded by the source corpus.

Objective This research examines 17-4 PH stainless steel powders produced by atomization in either argon or nitrogen atmospheres (producing martensitic (α-Fe) or mostly austenitic (γ-Fe) phase powders, respectively) and correspondingly fabricated by selective laser melting (SLM) in either a nitrogen or argon atmosphere. Methods Pre-alloyed 17-4 stainless steel powders prepared by atomization in either argon or nitrogen atmospheres were fabricated by SLM. The initial powder microstructures and phase structures were examined by light (optical) microscopy (OM), scanning electron microscopy (SEM), and X-ray diffraction (XRD). Prototypes fabricated by SLM were similarly characterized, and in addition transmission electron microscopy (TEM) characterization was also performed. Results Martensitic powder fabricated by SLM in nitrogen gas produced a martensitic product while pre-alloyed austenitic powder produced a primarily austenitic product. In contrast, both powders produced martensitic products when fabricated by SLM in argon gas. This unusual behavior occurred because of the rapid cooling affected by nitrogen versus argon cover gas as a consequence of a 40% greater thermal conductivity of nitrogen gas versus argon gas. SLM fabricated martensitic products exhibited HRC 30 in contrast to HRC 43 when aged at 482°C for 1 hour. Austenitic products did not exhibit age-hardening. Conclusions Using an argon cover gas, SLM-fabricated products are martensitic (and magnetic) with either an austenitic or martensitic pre-alloyed 17-4 PH stainless steel powder. Using a nitrogen cover gas, the product phase is the same as the precursor powder phase (austenitic or martensitic).

Subfields: Automotive Engineering, Mechanical Engineering

View Paper: https://www.semanticscholar.org/paper/5681b6edad12d84d5649e90d203f35a9fe55debd

How researchers see this paper

The researchers whose trusted networks rank it highest, strongest advocate first. Every researcher gets a different order.

In Automotive Engineering

1. T. Mukherjee
2. T. DebRoy
3. Nima Shamsaei
4. H. Wei
5. Amitava De
6. Aref Yadollahi
7. Wei Zhang
8. J. Elmer

In Mechanical Engineering

1. T. DebRoy
2. T. Mukherjee
3. H. Wei
4. Nima Shamsaei
5. Amitava De
6. Aref Yadollahi
7. J. Elmer
8. Wei Zhang

Citations in the corpus

• Additive manufacturing of steels: a review of achievements and challenges (2020, background): “Figure 12 Scatter plot showing ranges of elongation to failure against volume fraction of austenite reported in literature for 17–4 PH stainless steel samples made by additive manufacturing [129, 132, 134, 142, 145, 152, 153].”
• Additive manufacturing of metallic components – Process, structure and properties (2018, background): “As-built components consist of a mixture of austenite (50– 75 vol%) and martensite (25–50 vol%) built in nitrogen, and mostly martensite (92 vol%) built in argon [483,484].”
• Research status of laser additive manufacturing for metal: A review (2021, background): “[53] Murr LE, Martinez E, Hernandez J, Collins S, Amato KN, Gaytan SM, et al.”
• Additive manufacturing of metals (2016, background): “Experimental work [49,50] revealed that the type of gas used for the atomization influences the phase composition of the powder.”
• Corrosion performance of additively manufactured stainless steel parts: A review (2020, background): “Different classes of SS such as precipitation hardening stainless steels [7], tool steels [8], austenitic stainless steels [9], and maraging steels [10] are frequently used in additive manufacturing (AM).”