diff --git a/akka-docs-dev/rst/java/stream-graphs.rst b/akka-docs-dev/rst/java/stream-graphs.rst
index c9e6d89e60..96dfcd532d 100644
--- a/akka-docs-dev/rst/java/stream-graphs.rst
+++ b/akka-docs-dev/rst/java/stream-graphs.rst
@@ -200,10 +200,10 @@ Accessing the materialized value inside the Graph
 -------------------------------------------------
 
 In certain cases it might be necessary to feed back the materialized value of a Graph (partial, closed or backing a
-Source, Sink, Flow or BidiFlow). This is possible by using ``builder.matValue`` which gives an ``Outlet`` that
+Source, Sink, Flow or BidiFlow). This is possible by using ``builder.materializedValue`` which gives an ``Outlet`` that
 can be used in the graph as an ordinary source or outlet, and which will eventually emit the materialized value.
-If the materialized value is needed at more than one place, it is possible to call ``matValue`` any number of times
-to acquire the necessary number of outlets.
+If the materialized value is needed at more than one place, it is possible to call ``materializedValue`` any number of
+times to acquire the necessary number of outlets.
 
 .. includecode:: ../../../akka-samples/akka-docs-java-lambda/src/test/java/docs/stream/FlowGraphDocTest.java#flow-graph-matvalue
 
diff --git a/akka-docs-dev/rst/scala/code/docs/stream/FlowDocSpec.scala b/akka-docs-dev/rst/scala/code/docs/stream/FlowDocSpec.scala
index 59605e3079..9b5b97a146 100644
--- a/akka-docs-dev/rst/scala/code/docs/stream/FlowDocSpec.scala
+++ b/akka-docs-dev/rst/scala/code/docs/stream/FlowDocSpec.scala
@@ -190,7 +190,7 @@ class FlowDocSpec extends AkkaSpec {
     // It is also possible to map over the materialized values. In r9 we had a
     // doubly nested pair, but we want to flatten it out
     val r11: RunnableFlow[(Promise[Unit], Cancellable, Future[Int])] =
-      r9.mapMaterialized {
+      r9.mapMaterializedValue {
         case ((promise, cancellable), future) =>
           (promise, cancellable, future)
       }
diff --git a/akka-docs-dev/rst/scala/code/docs/stream/FlowGraphDocSpec.scala b/akka-docs-dev/rst/scala/code/docs/stream/FlowGraphDocSpec.scala
index 953a094d69..9f02dc1313 100644
--- a/akka-docs-dev/rst/scala/code/docs/stream/FlowGraphDocSpec.scala
+++ b/akka-docs-dev/rst/scala/code/docs/stream/FlowGraphDocSpec.scala
@@ -226,7 +226,7 @@ class FlowGraphDocSpec extends AkkaSpec {
     val foldFlow: Flow[Int, Int, Future[Int]] = Flow(Sink.fold[Int, Int](0)(_ + _)) {
       implicit builder ⇒
         fold ⇒
-          (fold.inlet, builder.matValue.mapAsync(4)(identity).outlet)
+          (fold.inlet, builder.materializedValue.mapAsync(4)(identity).outlet)
     }
     //#flow-graph-matvalue
 
@@ -243,8 +243,8 @@ class FlowGraphDocSpec extends AkkaSpec {
           //   fold completes
           // As a result this Source will never emit anything, and its materialited
           // Future will never complete
-          builder.matValue.mapAsync(4)(identity) ~> fold
-          builder.matValue.mapAsync(4)(identity).outlet
+          builder.materializedValue.mapAsync(4)(identity) ~> fold
+          builder.materializedValue.mapAsync(4)(identity).outlet
     }
     //#flow-graph-matvalue-cycle
   }
diff --git a/akka-docs-dev/rst/scala/stream-graphs.rst b/akka-docs-dev/rst/scala/stream-graphs.rst
index 27f36539cc..1f0942515b 100644
--- a/akka-docs-dev/rst/scala/stream-graphs.rst
+++ b/akka-docs-dev/rst/scala/stream-graphs.rst
@@ -254,10 +254,10 @@ Accessing the materialized value inside the Graph
 -------------------------------------------------
 
 In certain cases it might be necessary to feed back the materialized value of a Graph (partial, closed or backing a
-Source, Sink, Flow or BidiFlow). This is possible by using ``builder.matValue`` which gives an ``Outlet`` that
+Source, Sink, Flow or BidiFlow). This is possible by using ``builder.materializedValue`` which gives an ``Outlet`` that
 can be used in the graph as an ordinary source or outlet, and which will eventually emit the materialized value.
-If the materialized value is needed at more than one place, it is possible to call ``matValue`` any number of times
-to acquire the necessary number of outlets.
+If the materialized value is needed at more than one place, it is possible to call ``materializedValue`` any number of
+times to acquire the necessary number of outlets.
 
 .. includecode:: code/docs/stream/FlowGraphDocSpec.scala#flow-graph-matvalue
 
diff --git a/akka-http-core/src/main/scala/akka/http/impl/engine/rendering/BodyPartRenderer.scala b/akka-http-core/src/main/scala/akka/http/impl/engine/rendering/BodyPartRenderer.scala
index 151f3bcc0c..d0768924b9 100644
--- a/akka-http-core/src/main/scala/akka/http/impl/engine/rendering/BodyPartRenderer.scala
+++ b/akka-http-core/src/main/scala/akka/http/impl/engine/rendering/BodyPartRenderer.scala
@@ -33,7 +33,7 @@ private[http] object BodyPartRenderer {
 
         def bodyPartChunks(data: Source[ByteString, Any]): Source[ChunkStreamPart, Any] = {
           val entityChunks = data.map[ChunkStreamPart](Chunk(_))
-          (chunkStream(r.get) ++ entityChunks).mapMaterialized((_) ⇒ ())
+          (chunkStream(r.get) ++ entityChunks).mapMaterializedValue((_) ⇒ ())
         }
 
         def completePartRendering(): Source[ChunkStreamPart, Any] =
diff --git a/akka-http-core/src/main/scala/akka/http/impl/engine/rendering/RenderSupport.scala b/akka-http-core/src/main/scala/akka/http/impl/engine/rendering/RenderSupport.scala
index 3ebb0c8624..9738253b53 100644
--- a/akka-http-core/src/main/scala/akka/http/impl/engine/rendering/RenderSupport.scala
+++ b/akka-http-core/src/main/scala/akka/http/impl/engine/rendering/RenderSupport.scala
@@ -47,7 +47,7 @@ private object RenderSupport {
                         skipEntity: Boolean = false): Source[ByteString, Any] = {
     val messageStart = Source.single(r.get)
     val messageBytes =
-      if (!skipEntity) (messageStart ++ entityBytes).mapMaterialized(_ ⇒ ())
+      if (!skipEntity) (messageStart ++ entityBytes).mapMaterializedValue(_ ⇒ ())
       else CancelSecond(messageStart, entityBytes)
     messageBytes
   }
diff --git a/akka-http-core/src/main/scala/akka/http/impl/util/StreamUtils.scala b/akka-http-core/src/main/scala/akka/http/impl/util/StreamUtils.scala
index 32d7b1d690..fbfe1fc470 100644
--- a/akka-http-core/src/main/scala/akka/http/impl/util/StreamUtils.scala
+++ b/akka-http-core/src/main/scala/akka/http/impl/util/StreamUtils.scala
@@ -188,7 +188,7 @@ private[http] object StreamUtils {
    */
   def oneTimeSource[T, Mat](other: Source[T, Mat], errorMsg: String = "One time source can only be instantiated once"): Source[T, Mat] = {
     val onlyOnceFlag = new AtomicBoolean(false)
-    other.mapMaterialized { elem ⇒
+    other.mapMaterializedValue { elem ⇒
       if (onlyOnceFlag.get() || !onlyOnceFlag.compareAndSet(false, true))
         throw new IllegalStateException(errorMsg)
       elem
diff --git a/akka-http-core/src/main/scala/akka/http/javadsl/Http.scala b/akka-http-core/src/main/scala/akka/http/javadsl/Http.scala
index 08927ce3f9..1c4e43e0bc 100644
--- a/akka-http-core/src/main/scala/akka/http/javadsl/Http.scala
+++ b/akka-http-core/src/main/scala/akka/http/javadsl/Http.scala
@@ -47,7 +47,7 @@ class Http(system: ExtendedActorSystem) extends akka.actor.Extension {
   def bind(interface: String, port: Int, materializer: FlowMaterializer): Source[IncomingConnection, Future[ServerBinding]] =
     Source.adapt(delegate.bind(interface, port)(materializer)
       .map(new IncomingConnection(_))
-      .mapMaterialized(_.map(new ServerBinding(_))(ec)))
+      .mapMaterializedValue(_.map(new ServerBinding(_))(ec)))
 
   /**
    * Creates a [[Source]] of [[IncomingConnection]] instances which represents a prospective HTTP server binding
@@ -66,7 +66,7 @@ class Http(system: ExtendedActorSystem) extends akka.actor.Extension {
            materializer: FlowMaterializer): Source[IncomingConnection, Future[ServerBinding]] =
     Source.adapt(delegate.bind(interface, port, backlog, immutableSeq(options), settings, log)(materializer)
       .map(new IncomingConnection(_))
-      .mapMaterialized(_.map(new ServerBinding(_))(ec)))
+      .mapMaterializedValue(_.map(new ServerBinding(_))(ec)))
 
   /**
    * Convenience method which starts a new HTTP server at the given endpoint and uses the given ``handler``
@@ -173,7 +173,7 @@ class Http(system: ExtendedActorSystem) extends akka.actor.Extension {
     Flow.wrap {
       akka.stream.scaladsl.Flow[HttpRequest].map(_.asScala)
         .viaMat(delegate.outgoingConnection(host, port))(Keep.right)
-        .mapMaterialized(_.map(new OutgoingConnection(_))(ec))
+        .mapMaterializedValue(_.map(new OutgoingConnection(_))(ec))
     }
 
   /**
@@ -188,7 +188,7 @@ class Http(system: ExtendedActorSystem) extends akka.actor.Extension {
     Flow.wrap {
       akka.stream.scaladsl.Flow[HttpRequest].map(_.asScala)
         .viaMat(delegate.outgoingConnection(host, port, localAddress.asScala, immutableSeq(options), settings, log))(Keep.right)
-        .mapMaterialized(_.map(new OutgoingConnection(_))(ec))
+        .mapMaterializedValue(_.map(new OutgoingConnection(_))(ec))
     }
 
   /**
diff --git a/akka-http-core/src/main/scala/akka/http/scaladsl/Http.scala b/akka-http-core/src/main/scala/akka/http/scaladsl/Http.scala
index 307c023eeb..bfe26655c9 100644
--- a/akka-http-core/src/main/scala/akka/http/scaladsl/Http.scala
+++ b/akka-http-core/src/main/scala/akka/http/scaladsl/Http.scala
@@ -46,7 +46,7 @@ class HttpExt(config: Config)(implicit system: ActorSystem) extends akka.actor.E
       case Tcp.IncomingConnection(localAddress, remoteAddress, flow) ⇒
         val layer = serverLayer(settings, log)
         IncomingConnection(localAddress, remoteAddress, layer join flow)
-    }.mapMaterialized {
+    }.mapMaterializedValue {
       _.map(tcpBinding ⇒ ServerBinding(tcpBinding.localAddress)(() ⇒ tcpBinding.unbind()))(fm.executionContext)
     }
   }
@@ -367,7 +367,7 @@ class HttpExt(config: Config)(implicit system: ActorSystem) extends akka.actor.E
     import hcps._
     val theHostHeader = hostHeader(host, port, Uri.httpScheme(setup.encrypted))
     clientFlow[T](setup.settings)(_.withDefaultHeaders(theHostHeader) -> gatewayFuture)
-      .mapMaterialized(_ ⇒ HostConnectionPool(hcps)(gatewayFuture))
+      .mapMaterializedValue(_ ⇒ HostConnectionPool(hcps)(gatewayFuture))
   }
 
   private def clientFlow[T](settings: ConnectionPoolSettings)(f: HttpRequest ⇒ (HttpRequest, Future[PoolGateway]))(
diff --git a/akka-http-core/src/test/scala/akka/http/scaladsl/ClientServerSpec.scala b/akka-http-core/src/test/scala/akka/http/scaladsl/ClientServerSpec.scala
index 50214ab907..14f73a45f6 100644
--- a/akka-http-core/src/test/scala/akka/http/scaladsl/ClientServerSpec.scala
+++ b/akka-http-core/src/test/scala/akka/http/scaladsl/ClientServerSpec.scala
@@ -102,7 +102,7 @@ class ClientServerSpec extends WordSpec with Matchers with BeforeAndAfterAll {
       }
       "are triggered in `mapMaterialized`" in {
         val (_, hostname, port) = TestUtils.temporaryServerHostnameAndPort()
-        val flow = Flow[HttpRequest].map(_ ⇒ HttpResponse()).mapMaterialized(_ ⇒ sys.error("BOOM"))
+        val flow = Flow[HttpRequest].map(_ ⇒ HttpResponse()).mapMaterializedValue(_ ⇒ sys.error("BOOM"))
         val binding = Http().bindAndHandle(flow, hostname, port)
         val b1 = Await.result(binding, 3.seconds)
 
diff --git a/akka-http-core/src/test/scala/akka/http/scaladsl/TestServer.scala b/akka-http-core/src/test/scala/akka/http/scaladsl/TestServer.scala
index 4bb5c6b765..f9a4f3a996 100644
--- a/akka-http-core/src/test/scala/akka/http/scaladsl/TestServer.scala
+++ b/akka-http-core/src/test/scala/akka/http/scaladsl/TestServer.scala
@@ -70,7 +70,7 @@ object TestServer extends App {
     Flow[Message]
       .collect {
         case TextMessage.Strict(name)         ⇒ TextMessage.Strict(s"Hello '$name'")
-        case TextMessage.Streamed(nameStream) ⇒ TextMessage.Streamed(Source.single("Hello ") ++ nameStream mapMaterialized (_ ⇒ ()))
+        case TextMessage.Streamed(nameStream) ⇒ TextMessage.Streamed(Source.single("Hello ") ++ nameStream mapMaterializedValue (_ ⇒ ()))
         // ignore binary messages
       }
 }
diff --git a/akka-stream-tests/src/test/java/akka/stream/javadsl/FlowGraphTest.java b/akka-stream-tests/src/test/java/akka/stream/javadsl/FlowGraphTest.java
index da163fc315..d649c0a3b5 100644
--- a/akka-stream-tests/src/test/java/akka/stream/javadsl/FlowGraphTest.java
+++ b/akka-stream-tests/src/test/java/akka/stream/javadsl/FlowGraphTest.java
@@ -221,7 +221,7 @@ public class FlowGraphTest extends StreamTest {
       @Override
       public void apply(Builder<Future<Integer>> b, SinkShape<Integer> out) throws Exception {
         b.from(Source.single(1)).to(out);
-        b.from(b.matValue()).to(Sink.foreach(new Procedure<Future<Integer>>(){
+        b.from(b.materializedValue()).to(Sink.foreach(new Procedure<Future<Integer>>(){
           public void apply(Future<Integer> mat) throws Exception {
             probe.ref().tell(mat, ActorRef.noSender());
           }
diff --git a/akka-stream-tests/src/test/scala/akka/stream/scaladsl/GraphConcatSpec.scala b/akka-stream-tests/src/test/scala/akka/stream/scaladsl/GraphConcatSpec.scala
index 63c528e056..6b582b9caa 100644
--- a/akka-stream-tests/src/test/scala/akka/stream/scaladsl/GraphConcatSpec.scala
+++ b/akka-stream-tests/src/test/scala/akka/stream/scaladsl/GraphConcatSpec.scala
@@ -165,7 +165,7 @@ class GraphConcatSpec extends TwoStreamsSetup {
       m1.isInstanceOf[Unit] should be(true)
       m2.isInstanceOf[Unit] should be(true)
 
-      runnable.mapMaterialized((_) ⇒ "boo").run() should be("boo")
+      runnable.mapMaterializedValue((_) ⇒ "boo").run() should be("boo")
 
     }
 
@@ -179,7 +179,7 @@ class GraphConcatSpec extends TwoStreamsSetup {
       m2.isInstanceOf[Unit] should be(true)
       m3.isInstanceOf[Unit] should be(true)
 
-      runnable.mapMaterialized((_) ⇒ "boo").run() should be("boo")
+      runnable.mapMaterializedValue((_) ⇒ "boo").run() should be("boo")
 
     }
   }
diff --git a/akka-stream-tests/src/test/scala/akka/stream/scaladsl/GraphMatValueSpec.scala b/akka-stream-tests/src/test/scala/akka/stream/scaladsl/GraphMatValueSpec.scala
index 2474f523ef..1684da7498 100644
--- a/akka-stream-tests/src/test/scala/akka/stream/scaladsl/GraphMatValueSpec.scala
+++ b/akka-stream-tests/src/test/scala/akka/stream/scaladsl/GraphMatValueSpec.scala
@@ -28,7 +28,7 @@ class GraphMatValueSpec extends AkkaSpec {
       val f = FlowGraph.closed(foldSink) { implicit b ⇒
         fold ⇒
           Source(1 to 10) ~> fold
-          b.matValue.mapAsync(4)(identity) ~> Sink(sub)
+          b.materializedValue.mapAsync(4)(identity) ~> Sink(sub)
       }.run()
 
       val r1 = Await.result(f, 3.seconds)
@@ -45,8 +45,8 @@ class GraphMatValueSpec extends AkkaSpec {
         fold ⇒
           val zip = b.add(ZipWith[Int, Int, Int](_ + _))
           Source(1 to 10) ~> fold
-          b.matValue.mapAsync(4)(identity) ~> zip.in0
-          b.matValue.mapAsync(4)(identity) ~> zip.in1
+          b.materializedValue.mapAsync(4)(identity) ~> zip.in0
+          b.materializedValue.mapAsync(4)(identity) ~> zip.in1
 
           zip.out ~> Sink(sub)
       }.run()
@@ -62,7 +62,7 @@ class GraphMatValueSpec extends AkkaSpec {
     val foldFeedbackSource: Source[Future[Int], Future[Int]] = Source(foldSink) { implicit b ⇒
       fold ⇒
         Source(1 to 10) ~> fold
-        b.matValue
+        b.materializedValue
     }
 
     "allow exposing the materialized value as port" in {
@@ -72,7 +72,7 @@ class GraphMatValueSpec extends AkkaSpec {
     }
 
     "allow exposing the materialized value as port even if wrapped and the final materialized value is Unit" in {
-      val noMatSource: Source[Int, Unit] = foldFeedbackSource.mapAsync(4)(identity).map(_ + 100).mapMaterialized((_) ⇒ ())
+      val noMatSource: Source[Int, Unit] = foldFeedbackSource.mapAsync(4)(identity).map(_ + 100).mapMaterializedValue((_) ⇒ ())
       Await.result(noMatSource.runWith(Sink.head), 3.seconds) should ===(155)
     }
 
diff --git a/akka-stream/src/main/scala/akka/stream/javadsl/Flow.scala b/akka-stream/src/main/scala/akka/stream/javadsl/Flow.scala
index 313d38c165..b0d96c17cb 100644
--- a/akka-stream/src/main/scala/akka/stream/javadsl/Flow.scala
+++ b/akka-stream/src/main/scala/akka/stream/javadsl/Flow.scala
@@ -62,8 +62,8 @@ class Flow[-In, +Out, +Mat](delegate: scaladsl.Flow[In, Out, Mat]) extends Graph
   /**
    * Transform only the materialized value of this Flow, leaving all other properties as they were.
    */
-  def mapMaterialized[Mat2](f: function.Function[Mat, Mat2]): Flow[In, Out, Mat2] =
-    new Flow(delegate.mapMaterialized(f.apply _))
+  def mapMaterializedValue[Mat2](f: function.Function[Mat, Mat2]): Flow[In, Out, Mat2] =
+    new Flow(delegate.mapMaterializedValue(f.apply _))
 
   /**
    * Transform this [[Flow]] by appending the given processing steps.
@@ -593,7 +593,7 @@ class Flow[-In, +Out, +Mat](delegate: scaladsl.Flow[In, Out, Mat]) extends Graph
    * the first element emitted by the given ("second") source is emitted after the last element of this Flow.
    */
   def concat[M](second: Graph[SourceShape[Out @uncheckedVariance], M]): javadsl.Flow[In, Out, Mat @uncheckedVariance Pair M] =
-    new Flow(delegate.concat(second).mapMaterialized(p ⇒ Pair(p._1, p._2)))
+    new Flow(delegate.concat(second).mapMaterializedValue(p ⇒ Pair(p._1, p._2)))
 
   override def withAttributes(attr: OperationAttributes): javadsl.Flow[In, Out, Mat] =
     new Flow(delegate.withAttributes(attr))
@@ -690,15 +690,15 @@ trait RunnableFlow[+Mat] extends Graph[ClosedShape, Mat] {
   /**
    * Transform only the materialized value of this RunnableFlow, leaving all other properties as they were.
    */
-  def mapMaterialized[Mat2](f: function.Function[Mat, Mat2]): RunnableFlow[Mat2]
+  def mapMaterializedValue[Mat2](f: function.Function[Mat, Mat2]): RunnableFlow[Mat2]
 }
 
 /** INTERNAL API */
 private[akka] class RunnableFlowAdapter[Mat](runnable: scaladsl.RunnableFlow[Mat]) extends RunnableFlow[Mat] {
   def shape = ClosedShape
   def module = runnable.module
-  override def mapMaterialized[Mat2](f: function.Function[Mat, Mat2]): RunnableFlow[Mat2] =
-    new RunnableFlowAdapter(runnable.mapMaterialized(f.apply _))
+  override def mapMaterializedValue[Mat2](f: function.Function[Mat, Mat2]): RunnableFlow[Mat2] =
+    new RunnableFlowAdapter(runnable.mapMaterializedValue(f.apply _))
   override def run(materializer: FlowMaterializer): Mat = runnable.run()(materializer)
 
   override def withAttributes(attr: OperationAttributes): RunnableFlow[Mat] =
diff --git a/akka-stream/src/main/scala/akka/stream/javadsl/Graph.scala b/akka-stream/src/main/scala/akka/stream/javadsl/Graph.scala
index b0bd1caca0..1de59de601 100644
--- a/akka-stream/src/main/scala/akka/stream/javadsl/Graph.scala
+++ b/akka-stream/src/main/scala/akka/stream/javadsl/Graph.scala
@@ -300,7 +300,7 @@ object FlowGraph {
      *
      * @return The outlet that will emit the materialized value.
      */
-    def matValue: Outlet[Mat] = delegate.matValue
+    def materializedValue: Outlet[Mat] = delegate.materializedValue
 
     def run(mat: FlowMaterializer): Unit = delegate.buildRunnable().run()(mat)
 
diff --git a/akka-stream/src/main/scala/akka/stream/javadsl/Sink.scala b/akka-stream/src/main/scala/akka/stream/javadsl/Sink.scala
index 08b12ee49f..c993cf59a3 100644
--- a/akka-stream/src/main/scala/akka/stream/javadsl/Sink.scala
+++ b/akka-stream/src/main/scala/akka/stream/javadsl/Sink.scala
@@ -144,8 +144,8 @@ class Sink[-In, +Mat](delegate: scaladsl.Sink[In, Mat]) extends Graph[SinkShape[
   /**
    * Transform only the materialized value of this Sink, leaving all other properties as they were.
    */
-  def mapMaterialized[Mat2](f: function.Function[Mat, Mat2]): Sink[In, Mat2] =
-    new Sink(delegate.mapMaterialized(f.apply _))
+  def mapMaterializedValue[Mat2](f: function.Function[Mat, Mat2]): Sink[In, Mat2] =
+    new Sink(delegate.mapMaterializedValue(f.apply _))
 
   override def withAttributes(attr: OperationAttributes): javadsl.Sink[In, Mat] =
     new Sink(delegate.withAttributes(attr))
diff --git a/akka-stream/src/main/scala/akka/stream/javadsl/Source.scala b/akka-stream/src/main/scala/akka/stream/javadsl/Source.scala
index fde6b1e319..aee303aff8 100644
--- a/akka-stream/src/main/scala/akka/stream/javadsl/Source.scala
+++ b/akka-stream/src/main/scala/akka/stream/javadsl/Source.scala
@@ -236,8 +236,8 @@ class Source[+Out, +Mat](delegate: scaladsl.Source[Out, Mat]) extends Graph[Sour
   /**
    * Transform only the materialized value of this Source, leaving all other properties as they were.
    */
-  def mapMaterialized[Mat2](f: function.Function[Mat, Mat2]): Source[Out, Mat2] =
-    new Source(delegate.mapMaterialized(f.apply _))
+  def mapMaterializedValue[Mat2](f: function.Function[Mat, Mat2]): Source[Out, Mat2] =
+    new Source(delegate.mapMaterializedValue(f.apply _))
 
   /**
    * Transform this [[Source]] by appending the given processing stages.
diff --git a/akka-stream/src/main/scala/akka/stream/javadsl/Tcp.scala b/akka-stream/src/main/scala/akka/stream/javadsl/Tcp.scala
index b4df1b3d3e..3a08e91213 100644
--- a/akka-stream/src/main/scala/akka/stream/javadsl/Tcp.scala
+++ b/akka-stream/src/main/scala/akka/stream/javadsl/Tcp.scala
@@ -107,7 +107,7 @@ class Tcp(system: ExtendedActorSystem) extends akka.actor.Extension {
            idleTimeout: Duration): Source[IncomingConnection, Future[ServerBinding]] =
     Source.adapt(delegate.bind(interface, port, backlog, immutableSeq(options), idleTimeout)
       .map(new IncomingConnection(_))
-      .mapMaterialized(_.map(new ServerBinding(_))(ec)))
+      .mapMaterializedValue(_.map(new ServerBinding(_))(ec)))
 
   /**
    * Creates a [[Tcp.ServerBinding]] without specifying options.
@@ -116,7 +116,7 @@ class Tcp(system: ExtendedActorSystem) extends akka.actor.Extension {
   def bind(interface: String, port: Int): Source[IncomingConnection, Future[ServerBinding]] =
     Source.adapt(delegate.bind(interface, port)
       .map(new IncomingConnection(_))
-      .mapMaterialized(_.map(new ServerBinding(_))(ec)))
+      .mapMaterializedValue(_.map(new ServerBinding(_))(ec)))
 
   /**
    * Creates an [[Tcp.OutgoingConnection]] instance representing a prospective TCP client connection to the given endpoint.
@@ -127,7 +127,7 @@ class Tcp(system: ExtendedActorSystem) extends akka.actor.Extension {
                          connectTimeout: Duration,
                          idleTimeout: Duration): Flow[ByteString, ByteString, Future[OutgoingConnection]] =
     Flow.adapt(delegate.outgoingConnection(remoteAddress, localAddress, immutableSeq(options), connectTimeout, idleTimeout)
-      .mapMaterialized(_.map(new OutgoingConnection(_))(ec)))
+      .mapMaterializedValue(_.map(new OutgoingConnection(_))(ec)))
 
   /**
    * Creates an [[Tcp.OutgoingConnection]] without specifying options.
@@ -135,6 +135,6 @@ class Tcp(system: ExtendedActorSystem) extends akka.actor.Extension {
    */
   def outgoingConnection(host: String, port: Int): Flow[ByteString, ByteString, Future[OutgoingConnection]] =
     Flow.adapt(delegate.outgoingConnection(new InetSocketAddress(host, port))
-      .mapMaterialized(_.map(new OutgoingConnection(_))(ec)))
+      .mapMaterializedValue(_.map(new OutgoingConnection(_))(ec)))
 
 }
diff --git a/akka-stream/src/main/scala/akka/stream/scaladsl/Flow.scala b/akka-stream/src/main/scala/akka/stream/scaladsl/Flow.scala
index 2a30d45c79..cc08efca2c 100644
--- a/akka-stream/src/main/scala/akka/stream/scaladsl/Flow.scala
+++ b/akka-stream/src/main/scala/akka/stream/scaladsl/Flow.scala
@@ -68,7 +68,7 @@ final class Flow[-In, +Out, +Mat](private[stream] override val module: Module)
    * flow into the materialized value of the resulting Flow.
    */
   def viaMat[T, Mat2, Mat3](flow: Graph[FlowShape[Out, T], Mat2])(combine: (Mat, Mat2) ⇒ Mat3): Flow[In, T, Mat3] = {
-    if (this.isIdentity) flow.asInstanceOf[Flow[In, T, Mat2]].mapMaterialized(combine(().asInstanceOf[Mat], _))
+    if (this.isIdentity) flow.asInstanceOf[Flow[In, T, Mat2]].mapMaterializedValue(combine(().asInstanceOf[Mat], _))
     else {
       val flowCopy = flow.module.carbonCopy
       new Flow(
@@ -129,7 +129,7 @@ final class Flow[-In, +Out, +Mat](private[stream] override val module: Module)
   /**
    * Transform the materialized value of this Flow, leaving all other properties as they were.
    */
-  def mapMaterialized[Mat2](f: Mat ⇒ Mat2): Repr[Out, Mat2] =
+  def mapMaterializedValue[Mat2](f: Mat ⇒ Mat2): Repr[Out, Mat2] =
     new Flow(module.transformMaterializedValue(f.asInstanceOf[Any ⇒ Any]))
 
   /**
@@ -320,7 +320,7 @@ case class RunnableFlow[+Mat](private[stream] val module: StreamLayout.Module) e
   /**
    * Transform only the materialized value of this RunnableFlow, leaving all other properties as they were.
    */
-  def mapMaterialized[Mat2](f: Mat ⇒ Mat2): RunnableFlow[Mat2] =
+  def mapMaterializedValue[Mat2](f: Mat ⇒ Mat2): RunnableFlow[Mat2] =
     copy(module.transformMaterializedValue(f.asInstanceOf[Any ⇒ Any]))
 
   /**
diff --git a/akka-stream/src/main/scala/akka/stream/scaladsl/Graph.scala b/akka-stream/src/main/scala/akka/stream/scaladsl/Graph.scala
index 19c874694e..7d55055785 100644
--- a/akka-stream/src/main/scala/akka/stream/scaladsl/Graph.scala
+++ b/akka-stream/src/main/scala/akka/stream/scaladsl/Graph.scala
@@ -367,7 +367,7 @@ object FlowGraph extends GraphApply {
      *
      * @return The outlet that will emit the materialized value.
      */
-    def matValue: Outlet[M] = {
+    def materializedValue: Outlet[M] = {
       val module = new MaterializedValueSource[Any]
       moduleInProgress = moduleInProgress.grow(module)
       module.shape.outlet.asInstanceOf[Outlet[M]]
diff --git a/akka-stream/src/main/scala/akka/stream/scaladsl/Sink.scala b/akka-stream/src/main/scala/akka/stream/scaladsl/Sink.scala
index efdd8c3a9f..d1d784fc85 100644
--- a/akka-stream/src/main/scala/akka/stream/scaladsl/Sink.scala
+++ b/akka-stream/src/main/scala/akka/stream/scaladsl/Sink.scala
@@ -37,7 +37,7 @@ final class Sink[-In, +Mat](private[stream] override val module: Module)
   def runWith[Mat2](source: Graph[SourceShape[In], Mat2])(implicit materializer: FlowMaterializer): Mat2 =
     Source.wrap(source).to(this).run()
 
-  def mapMaterialized[Mat2](f: Mat ⇒ Mat2): Sink[In, Mat2] =
+  def mapMaterializedValue[Mat2](f: Mat ⇒ Mat2): Sink[In, Mat2] =
     new Sink(module.transformMaterializedValue(f.asInstanceOf[Any ⇒ Any]))
 
   override def withAttributes(attr: OperationAttributes): Sink[In, Mat] =
diff --git a/akka-stream/src/main/scala/akka/stream/scaladsl/Source.scala b/akka-stream/src/main/scala/akka/stream/scaladsl/Source.scala
index cdfd3e0c36..acb1cd6e10 100644
--- a/akka-stream/src/main/scala/akka/stream/scaladsl/Source.scala
+++ b/akka-stream/src/main/scala/akka/stream/scaladsl/Source.scala
@@ -84,7 +84,7 @@ final class Source[+Out, +Mat](private[stream] override val module: Module)
   /**
    * Transform only the materialized value of this Source, leaving all other properties as they were.
    */
-  def mapMaterialized[Mat2](f: Mat ⇒ Mat2): Repr[Out, Mat2] =
+  def mapMaterializedValue[Mat2](f: Mat ⇒ Mat2): Repr[Out, Mat2] =
     new Source(module.transformMaterializedValue(f.asInstanceOf[Any ⇒ Any]))
 
   /** INTERNAL API */